Method and device for performing positioning by means of beamformed signal in wireless communication system

ABSTRACT

The present disclosure is for performing positioning by means of a beamformed signal in a wireless communication system. An operation method by a terminal in a wireless communication system can comprise the steps of: transmitting first messages requesting transmission of a positioning reference signal (PRS) by means of a plurality of transmission beams; receiving from a second terminal a second message indicating at least one transmission beam among the plurality of transmission beams; transmitting a third message, comprising scheduling information for transmission of the PRS, to the second terminal by means of the transmission beam; and receiving the PRS from the second terminal on the basis of the scheduling information.

TECHNICAL FIELD

The present disclosure relates to a wireless communication system and,more particularly, to a method and device for performing positioningusing a beamformed signal in a wireless communication system.

BACKGROUND ART

A wireless communication system is a multiple access system thatsupports communication of multiple users by sharing available systemresources (e.g., a bandwidth, transmission power, etc.). Examples ofmultiple access systems include a code division multiple access (CDMA)system, a frequency division multiple access (FDMA) system, a timedivision multiple access (TDMA) system, an orthogonal frequency divisionmultiple access (OFDMA) system, a single carrier frequency divisionmultiple access (SC-FDMA) system, and a multi carrier frequency divisionmultiple access (MC-FDMA) system.

Sidelink (SL) communication is a communication scheme in which a directlink is established between User Equipments (UEs) and the UEs exchangevoice and data directly with each other without intervention of anevolved Node B (eNB). SL communication is under consideration as asolution to the overhead of an eNB caused by rapidly increasing datatraffic.

Vehicle-to-everything (V2X) refers to a communication technology throughwhich a vehicle exchanges information with another vehicle, apedestrian, an object having an infrastructure (or infra) establishedtherein, and so on. The V2X may be divided into 4 types, such asvehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I),vehicle-to-network (V2N), and vehicle-to-pedestrian (V2P). The V2Xcommunication may be provided via a PC5 interface and/or Uu interface.

Meanwhile, as a wider range of communication devices require largercommunication capacities, the need for mobile broadband communicationthat is more enhanced than the existing Radio Access Technology (RAT) isrising. Accordingly, discussions are made on services and user equipment(UE) that are sensitive to reliability and latency. And, a nextgeneration radio access technology that is based on the enhanced mobilebroadband communication, massive Machine Type Communication (mMTC),Ultra-Reliable and Low Latency Communication (URLLC), and so on, may bereferred to as a new radio access technology (RAT) or new radio (NR).Herein, the NR may also support vehicle-to-everything (V2X)communication.

DISCLOSURE Technical Problem

The present disclosure relates to a method and device for efficientlyperforming positioning in a wireless communication system.

The present disclosure relates to a method and device for performingpositioning using a beamformed signal in a wireless communicationsystem.

The present disclosure relates to a method and device for reducing atime required for positioning in a wireless communication system.

The present disclosure relates to a method and device for simultaneouslyperforming beamforming management and positioning preparation proceduresin a wireless communication system.

The technical objects to be achieved in the present disclosure are notlimited to the above-mentioned technical objects, and other technicalobjects that are not mentioned may be considered by those skilled in theart through the embodiments described below.

Technical Solution

As an example of the present disclosure, a method of operating a firstterminal in a wireless communication system may comprise transmittingfirst messages requesting to transmit a positioning reference signal(PRS) using a plurality of transmit beams, receiving, from a secondterminal, a second message indicating at least one transmit beam amongthe plurality of transmit beams, transmitting, to the second terminal, athird message including scheduling information for transmission of thePRS using the transmit beam, and receiving, from the second terminal,the PRS based on the scheduling information.

As an example of the present disclosure, a method of operating a secondterminal in a wireless communication system may comprise receiving atleast one of first messages requesting to transmit a positioningreference signal (PRS) transmitted by a first terminal using a pluralityof transmit beams, transmitting, to the first terminal, a second messageindicating at least one transmit beam among the plurality of transmitbeams, receiving a third message including scheduling information fortransmission of the PRS transmitted by the first terminal using the atleast one transmit beam, and transmitting, to the first terminal, thePRS based on the scheduling information.

As an example of the present disclosure, a first terminal in a wirelesscommunication system may comprise a transceiver and a processorconnected to the transceiver. The processor may perform control totransmit first messages requesting to transmit a positioning referencesignal (PRS) using a plurality of transmit beams, to receive, from asecond terminal, a second message indicating at least one transmit beamamong the plurality of transmit beams, to transmit, to the secondterminal, a third message including scheduling information fortransmission of the PRS using the transmit beam, and to receive, fromthe second terminal, the PRS based on the scheduling information.

As an example of the present disclosure, a second terminal in a wirelesscommunication system may comprise a transceiver and a processorconnected to the transceiver. The processor may perform control toreceive at least one of first messages requesting to transmit apositioning reference signal (PRS) transmitted by a first terminal usinga plurality of transmit beams, to transmit, to the first terminal, asecond message indicating at least one transmit beam among the pluralityof transmit beams, to receive a third message including schedulinginformation for transmission of the PRS transmitted by the firstterminal using the at least one transmit beam and to transmit, to thefirst terminal, the PRS based on the scheduling information.

As an example of the present disclosure, a first device may comprise atleast one memory and at least one processor functionally connected tothe at least one memory. The at least one processor may control thefirst device to transmit first messages requesting to transmit apositioning reference signal (PRS) using a plurality of transmit beams,to receive, from a second terminal, a second message indicating at leastone transmit beam among the plurality of transmit beams, to transmit, tothe second terminal, a third message including scheduling informationfor transmission of the PRS using the transmit beam and to receive, fromthe second terminal, the PRS based on the scheduling information.

As an example of the present disclosure, a non-transitorycomputer-readable medium storing at least one instruction may comprisethe at least one instruction executable by a processor. The at least oneinstruction instructs a first device to transmit first messagesrequesting to transmit a positioning reference signal (PRS) using aplurality of transmit beams, to receive, from a second device, a secondmessage indicating at least one transmit beam among the plurality oftransmit beams, to transmit, to the second device, a third messageincluding scheduling information for transmission of the PRS using thetransmit beam and to receive, from the second device, the PRS based onthe scheduling information.

The above-described aspects of the present disclosure are merely some ofthe preferred embodiments of the present disclosure, and variousembodiments reflecting the technical features of the present disclosuremay be derived and understood by those of ordinary skill in the artbased on the following detailed description of the disclosure.

Advantageous Effects

As is apparent from the above description, the embodiments of thepresent disclosure have the following effects.

According to the present disclosure, positioning may be efficientlyperformed in a wireless communication system.

In addition, according to the present disclosure, when a positioningreference signal (PRS) transmission request and scheduling procedure anda beam management procedure are separately performed in a millimeterwave (mm Wave) band, a time required to request and receive the PRS maybe further reduced.

It will be appreciated by persons skilled in the art that that theeffects that can be achieved through the embodiments of the presentdisclosure are not limited to those described above and otheradvantageous effects of the present disclosure will be more clearlyunderstood from the following detailed description. That is, unintendedeffects according to implementation of the present disclosure may bederived by those skilled in the art from the embodiments of the presentdisclosure.

DESCRIPTION OF DRAWINGS

The accompanying drawings are provided to help understanding of thepresent disclosure, and may provide embodiments of the presentdisclosure together with a detailed description. However, the technicalfeatures of the present disclosure are not limited to specific drawings,and the features disclosed in each drawing may be combined with eachother to constitute a new embodiment. Reference numerals in each drawingmay refer to structural elements.

FIG. 1 illustrates a structure of a wireless communication system, inaccordance with an embodiment of the present disclosure.

FIG. 2 illustrates a functional division between an NG-RAN and a SGC, inaccordance with an embodiment of the present disclosure.

FIGS. 3 illustrates a radio protocol architecture, in accordance with anembodiment of the present disclosure.

FIG. 4 illustrates a structure of a radio frame in an NR system, inaccordance with an embodiment of the present disclosure.

FIG. 5 illustrates a structure of a slot in an NR frame, in accordancewith an embodiment of the present disclosure.

FIG. 6 illustrates an example of a BWP, in accordance with an embodimentof the present disclosure.

FIGS. 7A and 7B illustrate a radio protocol architecture for a SLcommunication, in accordance with an embodiment of the presentdisclosure.

FIG. 8 illustrates a synchronization source or synchronization referenceof V2X, in accordance with an embodiment of the present disclosure.

FIGS. 9A and 9B illustrate a procedure of performing V2X or SLcommunication by a terminal based on a transmission mode, in accordancewith an embodiment of the present disclosure.

FIGS. 10A to 10C illustrate three cast types, in accordance with anembodiment of the present disclosure.

FIG. 11 illustrates a resource unit for channel busy ratio (CBR)measurement, in accordance with an embodiment of the present disclosure;

FIG. 12 illustrates an example of an architecture in a 5G system, forpositioning a UE which has accessed an NG-RAN or an evolved UMTSterrestrial radio access network (E-UTRAN), in accordance with anembodiment of the present disclosure;

FIG. 13 illustrates an implementation example of a network forpositioning a UE, in accordance with an embodiment of the presentdisclosure;

FIG. 14 illustrates exemplary protocol layers used to support LTEpositioning protocol (LPP) message transmission between a locationmanagement function (LMF) and a UE, in accordance with an embodiment ofthe present disclosure;

FIG. 15 illustrates exemplary protocol layers used to support NRpositioning protocol A (NRPPa) protocol data unit (PDU) transmissionbetween an LMF and an NG-RAN node, in accordance with an embodiment ofthe present disclosure;

FIG. 16 illustrates an observed time difference of arrival (OTDOA)positioning method, in accordance with an embodiment of the presentdisclosure;

FIG. 17 illustrates the concept of a positioning procedure based on apositioning reference signal (PRS) request in a wireless communicationsystem according to an embodiment of the present disclosure.

FIG. 18 illustrates an example of a method of operating a terminal forperforming positioning in a wireless communication system according toan embodiment of the present disclosure.

FIG. 19 illustrates an example of a method of operating a terminalassisting positioning in a wireless communication system according to anembodiment of the present disclosure.

FIG. 20 illustrates an example of a procedure for transmitting a PRSbased on a request in a wireless communication system according to anembodiment of the present disclosure.

FIG. 21 illustrates an example of resource pools allocated for eachservice in a wireless communication system according to an embodiment ofthe present disclosure.

FIG. 22 illustrates an example of resource pools allocated for each beamin a wireless communication system according to an embodiment of thepresent disclosure.

FIG. 23 illustrates a communication system, in accordance with anembodiment of the present disclosure.

FIG. 24 illustrates wireless devices, in accordance with an embodimentof the present disclosure.

FIG. 25 illustrates a signal process circuit for a transmission signal,in accordance with an embodiment of the present disclosure.

FIG. 26 illustrates a wireless device, in accordance with an embodimentof the present disclosure.

FIG. 27 illustrates a hand-held device, in accordance with an embodimentof the present disclosure.

FIG. 28 illustrates a car or an autonomous vehicle, in accordance withan embodiment of the present disclosure.

MODE FOR INVENTION

The embodiments of the present disclosure described below arecombinations of elements and features of the present disclosure inspecific forms. The elements or features may be considered selectiveunless otherwise mentioned. Each element or feature may be practicedwithout being combined with other elements or features. Further, anembodiment of the present disclosure may be constructed by combiningparts of the elements and/or features. Operation orders described inembodiments of the present disclosure may be rearranged. Someconstructions or elements of any one embodiment may be included inanother embodiment and may be replaced with corresponding constructionsor features of another embodiment.

In the description of the drawings, procedures or steps which render thescope of the present disclosure unnecessarily ambiguous will be omittedand procedures or steps which can be understood by those skilled in theart will be omitted.

Throughout the specification, when a certain portion “includes” or“comprises” a certain component, this indicates that other componentsare not excluded and may be further included unless otherwise noted. Theterms “unit”, “-or/er” and “module” described in the specificationindicate a unit for processing at least one function or operation, whichmay be implemented by hardware, software or a combination thereof. Inaddition, the terms “a or an”, “one”, “the” etc. may include a singularrepresentation and a plural representation in the context of the presentdisclosure (more particularly, in the context of the following claims)unless indicated otherwise in the specification or unless contextclearly indicates otherwise.

In the present specification, “A or B” may mean “only A”, “only B” or“both A and B.” In other words, in the present specification, “A or B”may be interpreted as “A and/or B”. For example, in the presentspecification, “A, B, or C” may mean “only A”, “only B”, “only C”, or“any combination of A, B, C”.

A slash (/) or comma used in the present specification may mean“and/or”. For example, “A/B” may mean “A and/or B”. Accordingly, “A/B”may mean “only A”, “only B”, or “both A and B”. For example, “A, B, C”may mean “A, B, or C”.

In the present specification, “at least one of A and B” may mean “onlyA”, “only B”, or “both A and B”. In addition, in the presentspecification, the expression “at least one of A or B” or “at least oneof A and/or B” may be interpreted as “at least one of A and B”.

In addition, in the present specification, “at least one of A, B, and C”may mean “only A”, “only B”, “only C”, or “any combination of A, B, andC”. In addition, “at least one of A, B, or C” or “at least one of A, B,and/or C” may mean “at least one of A, B, and C”.

In addition, a parenthesis used in the present specification may mean“for example”. Specifically, when indicated as “control information(PDCCH)”, it may mean that “PDCCH” is proposed as an example of the“control information”. In other words, the “control information” of thepresent specification is not limited to “PDCCH”, and “PDDCH” may beproposed as an example of the “control information”. In addition, whenindicated as “control information (i.e., PDCCH)”, it may also mean that“PDCCH” is proposed as an example of the “control information”.

In the following description, ‘when, if, or in case of’ may be replacedwith ‘based on’.

A technical feature described individually in one figure in the presentspecification may be individually implemented, or may be simultaneouslyimplemented.

In the present disclosure, a higher layer parameter may be a parameterwhich is configured, pre-configured or pre-defined for a UE. Forexample, a base station or a network may transmit the higher layerparameter to the UE. For example, the higher layer parameter may betransmitted through radio resource control (RRC) signaling or mediumaccess control (MAC) signaling.

The technology described below may be used in various wirelesscommunication systems such as code division multiple access (CDMA),frequency division multiple access (FDMA), time division multiple access(TDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and so on. TheCDMA may be implemented with a radio technology, such as universalterrestrial radio access (UTRA) or CDMA-2000. The TDMA may beimplemented with a radio technology, such as global system for mobilecommunications (GSM)/general packet ratio service (GPRS)/enhanced datarate for GSM evolution (EDGE). The OFDMA may be implemented with a radiotechnology, such as institute of electrical and electronics engineers(IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, evolved UTRA(E-UTRA), and so on. IEEE 802.16m is an evolved version of IEEE 802.16eand provides backward compatibility with a system based on the IEEE802.16e. The UTRA is part of a universal mobile telecommunication system(UMTS). 3rd generation partnership project (3GPP) long term evolution(LTE) is part of an evolved UMTS (E-UMTS) using the E-UTRA. The 3GPP LTEuses the OFDMA in a downlink and uses the SC-FDMA in an uplink.LTE-advanced (LTE-A) is an evolution of the LTE.

5G NR is a successive technology of LTE-A corresponding to a newClean-slate type mobile communication system having the characteristicsof high performance, low latency, high availability, and so on. 5G NRmay use resources of all spectrum available for usage including lowfrequency bands of less than 1 GHz, middle frequency bands ranging from1 GHz to 10 GHz, high frequency (millimeter waves) of 24 GHz or more,and so on.

For clarity in the description, the following description will mostlyfocus on LTE-A or 5G NR. However, technical features according to anembodiment of the present disclosure will not be limited only to this.

For terms and techniques not specifically described among terms andtechniques used in the present disclosure, reference may be made to awireless communication standard document published before the presentdisclosure is filed. For example, the following document may be referredto.

(1) 3GPP LTE

-   3GPP TS 36.211: Physical channels and modulation-   3GPP TS 36.212: Multiplexing and channel coding-   3GPP TS 36.213: Physical layer procedures-   3GPP TS 36.214: Physical layer; Measurements-   3GPP TS 36.300: Overall description-   3GPP TS 36.304: User Equipment (UE) procedures in idle mode-   3GPP TS 36.314: Layer 2 - Measurements-   3GPP TS 36.321: Medium Access Control (MAC) protocol-   3GPP TS 36.322: Radio Link Control (RLC) protocol-   3GPP TS 36.323: Packet Data Convergence Protocol (PDCP)-   3GPP TS 36.331: Radio Resource Control (RRC) protocol

(2) 3GPP NR (e.g. 5G)

-   3GPP TS 38.211: Physical channels and modulation-   3GPP TS 38.212: Multiplexing and channel coding-   3GPP TS 38.213: Physical layer procedures for control-   3GPP TS 38.214: Physical layer procedures for data-   3GPP TS 38.215: Physical layer measurements-   3GPP TS 38.300: Overall description-   3GPP TS 38.304: User Equipment (UE) procedures in idle mode and in    RRC inactive state-   3GPP TS 38.321: Medium Access Control (MAC) protocol-   3GPP TS 38.322: Radio Link Control (RLC) protocol-   3GPP TS 38.323: Packet Data Convergence Protocol (PDCP)-   3GPP TS 38.331: Radio Resource Control (RRC) protocol-   3GPP TS 37.324: Service Data Adaptation Protocol (SDAP)-   3GPP TS 37.340: Multi-connectivity; Overall description

COMMUNICATION SYSTEM APPLICABLE TO THE PRESENT DISCLOSURE

FIG. 1 illustrates a structure of a wireless communication systemaccording to an embodiment of the present disclosure. The embodiment ofFIG. 1 may be combined with various embodiments of the presentdisclosure.

Referring to FIG. 1 , a wireless communication system includes a radioaccess network (RAN) 102 and a core network 103. The radio accessnetwork 102 includes a base station 120 that provides a control planeand a user plane to a terminal 110. The terminal 110 may be fixed ormobile, and may be called other terms such as a user equipment (UE), amobile station (MS), a subscriber station (SS), a mobile subscriberstation (MSS), a mobile terminal, an advanced mobile station (AMS), or awireless device. The base station 120 refers to a node that provides aradio access service to the terminal 110, and may be called other termssuch as a fixed station, a Node B, an eNB (eNode B), a gNB (gNode B), anng-eNB, an advanced base station (ABS), an access point, a basetransceiver system (BTS), or an access point (AP). The core network 103includes a core network entity 130. The core network entity 130 may bedefined in various ways according to functions, and may be called otherterms such as a core network node, a network node, or a networkequipment.

Components of a system may be referred to differently according to anapplied system standard. In the case of the LTE or LTE-A standard, theradio access network 102 may be referred to as an Evolved-UMTSTerrestrial Radio Access Network (E-UTRAN), and the core network 103 maybe referred to as an evolved packet core (EPC). In this case, the corenetwork 103 includes a Mobility Management Entity (MME), a ServingGateway (S-GW), and a packet data network-gateway (P-GW). The MME hasaccess information of the terminal or information on the capability ofthe terminal, and this information is mainly used for mobilitymanagement of the terminal. The S-GW is a gateway having an E-UTRAN asan endpoint, and the P-GW is a gateway having a packet data network(PDN) as an endpoint.

In the case of the 5G NR standard, the radio access network 102 may bereferred to as an NG-RAN, and the core network 103 may be referred to asa 5GC (5G core). In this case, the core network 103 includes an accessand mobility management function (AMF), a user plane function (UPF), anda session management function (SMF). The AMF provides a function foraccess and mobility management in units of terminals, the UPF performs afunction of mutually transmitting data units between an upper datanetwork and the radio access network 102, and the SMF provides a sessionmanagement function.

The BSs 120 may be connected to one another via Xn interface. The BS 120may be connected to one another via core network 103 and NG interface.More specifically, the BSs 130 may be connected to an access andmobility management function (AMF) via NG-C interface, and may beconnected to a user plane function (UPF) via NG-U interface.

FIG. 2 illustrates a functional division between an NG-RAN and a 5GC, inaccordance with an embodiment of the present disclosure. The embodimentof FIG. 2 may be combined with various embodiments of the presentdisclosure.

Referring to FIG. 2 , the gNB may provide functions, such as Inter CellRadio Resource Management (RRM), Radio Bearer (RB) control, ConnectionMobility Control, Radio Admission Control, Measurement Configuration &Provision, Dynamic Resource Allocation, and so on. An AMF may providefunctions, such as Non Access Stratum (NAS) security, idle statemobility processing, and so on. A UPF may provide functions, such asMobility Anchoring, Protocol Data Unit (PDU) processing, and so on. ASession Management Function (SMF) may provide functions, such as userequipment (UE) Internet Protocol (IP) address allocation, PDU sessioncontrol, and so on.

Layers of a radio interface protocol between the UE and the network canbe classified into a first layer (layer 1, L1), a second layer (layer 2,L2), and a third layer (layer 3, L3) based on the lower three layers ofthe open system interconnection (OSI) model that is well-known in thecommunication system. Among them, a physical (PHY) layer belonging tothe first layer provides an information transfer service by using aphysical channel, and a radio resource control (RRC) layer belonging tothe third layer serves to control a radio resource between the UE andthe network. For this, the RRC layer enable to exchange an RRC messagebetween the UE and the BS.

FIGS. 3A and 3B illustrate a radio protocol architecture, in accordancewith an embodiment of the present disclosure. The embodiment of FIG. 3may be combined with various embodiments of the present disclosure.Specifically, FIG. 3A exemplifies a radio protocol architecture for auser plane, and FIG. 3B exemplifies a radio protocol architecture for acontrol plane. The user plane corresponds to a protocol stack for userdata transmission, and the control plane corresponds to a protocol stackfor control signal transmission.

Referring to FIGS. 3A and 3B, a physical layer provides an upper layerwith an information transfer service through a physical channel. Thephysical layer is connected to a medium access control (MAC) layer whichis an upper layer of the physical layer through a transport channel.Data is transferred between the MAC layer and the physical layer throughthe transport channel. The transport channel is classified according tohow and with what characteristics data is transmitted through a radiointerface.

Between different physical layers, i.e., a physical layer of atransmitter and a physical layer of a receiver, data are transferredthrough the physical channel. The physical channel is modulated using anorthogonal frequency division multiplexing (OFDM) scheme, and utilizestime and frequency as a radio resource.

The MAC layer provides services to a radio link control (RLC) layer,which is a higher layer of the MAC layer, via a logical channel. The MAClayer provides a function of mapping multiple logical channels tomultiple transport channels. The MAC layer also provides a function oflogical channel multiplexing by mapping multiple logical channels to asingle transport channel. The MAC layer provides data transfer servicesover logical channels.

The RLC layer performs concatenation, segmentation, and reassembly ofRadio Link Control Service Data Unit (RLC SDU). In order to ensurediverse quality of service (QoS) required by a radio bearer (RB), theRLC layer provides three types of operation modes, i.e., a transparentmode (TM), an unacknowledged mode (UM), and an acknowledged mode (AM).An AM RLC provides error correction through an automatic repeat request(ARQ).

A radio resource control (RRC) layer is defined only in the controlplane. The RRC layer serves to control the logical channel, thetransport channel, and the physical channel in association withconfiguration, reconfiguration and release of RBs. The RB is a logicalpath provided by the first layer (i.e., the physical layer or the PI-TYlayer) and the second layer (i.e., the MAC layer, the RLC layer, and thepacket data convergence protocol (PDCP) layer) for data delivery betweenthe UE and the network.

Functions of a packet data convergence protocol (PDCP) layer in the userplane include user data delivery, header compression, and ciphering.Functions of a PDCP layer in the control plane include control-planedata delivery and ciphering/integrity protection.

A service data adaptation protocol (SDAP) layer is defined only in auser plane. The SDAP layer performs mapping between a Quality of Service(QoS) flow and a data radio bearer (DRB) and QoS flow ID (QFI) markingin both DL and UL packets.

The configuration of the RB implies a process for specifying a radioprotocol layer and channel properties to provide a particular serviceand for determining respective detailed parameters and operations. TheRB can be classified into two types, i.e., a signaling RB (SRB) and adata RB (DRB). The SRB is used as a path for transmitting an RRC messagein the control plane. The DRB is used as a path for transmitting userdata in the user plane.

When an RRC connection is established between an RRC layer of the UE andan RRC layer of the E-UTRAN, the UE is in an RRC_CONNECTED state, and,otherwise, the UE may be in an RRC_IDLE state. In case of the NR, anRRC_INACTIVE state is additionally defined, and a UE being in theRRC_INACTIVE state may maintain its connection with a core networkwhereas its connection with the BS is released.

Data is transmitted from the network to the UE through a downlinktransport channel. Examples of the downlink transport channel include abroadcast channel (BCH) for transmitting system information and adownlink-shared channel (SCH) for transmitting user traffic or controlmessages. Traffic of downlink multicast or broadcast services or thecontrol messages can be transmitted on the downlink-SCH or an additionaldownlink multicast channel (MCH). Data is transmitted from the UE to thenetwork through an uplink transport channel. Examples of the uplinktransport channel include a random access channel (RACH) fortransmitting an initial control message and an uplink SCH fortransmitting user traffic or control messages.

Examples of logical channels belonging to a higher channel of thetransport channel and mapped onto the transport channels include abroadcast channel (BCCH), a paging control channel (PCCH), a commoncontrol channel (CCCH), a multicast control channel (MCCH), a multicasttraffic channel (MTCH), etc.

The physical channel includes several OFDM symbols in a time domain andseveral sub-carriers in a frequency domain. One sub-frame includes aplurality of OFDM symbols in the time domain. A resource block is a unitof resource allocation, and consists of a plurality of OFDM symbols anda plurality of sub-carriers. Further, each subframe may use specificsub-carriers of specific OFDM symbols (e.g., a first OFDM symbol) of acorresponding subframe for a physical downlink control channel (PDCCH),i.e., an L1/L2 control channel. A transmission time interval (TTI) is aunit time of subframe transmission.

Radio Resource Structure

FIG. 4 illustrates a structure of a radio frame in an NR system, inaccordance with an embodiment of the present disclosure. The embodimentof FIG. 4 may be combined with various embodiments of the presentdisclosure.

Referring to FIG. 4 , in the NR, a radio frame may be used forperforming uplink and downlink transmission. A radio frame has a lengthof 10 ms and may be defined to be configured of two half-frames (HFs). Ahalf-frame may include five 1 ms subframes (SFs). A subframe (SF) may bedivided into one or more slots, and the number of slots within asubframe may be determined in accordance with subcarrier spacing (SCS).Each slot may include 12 or 14 OFDM(A) symbols according to a cyclicprefix (CP).

In case of using a normal CP, each slot may include 14 symbols. In caseof using an extended CP, each slot may include 12 symbols. Herein, asymbol may include an OFDM symbol (or CP-OFDM symbol) and a SingleCarrier-FDMA (SC-FDMA) symbol (or Discrete Fourier Transform-spread-OFDM(DFT-s-OFDM) symbol).

In a case where a normal CP is used, a number of symbols per slot(N^(slot) _(symb)), a number slots per frame (N^(frame,µ) _(slot)), anda number of slots per subframe (N^(subframe,µ) _(slot)) may be variedbased on an SCS configuration (µ). For instance, SCS (=15*2^(µ)),N^(slot) _(symb), N^(frame,µ) _(slot) and N^(subframe,µ) _(slot) are 15KHz, 14, 10 and 1, respectively, when µ=0, are 30 KHz, 14, 20 and 2,respectively, when µ=1, are 60 KHz, 14, 40 and 4, respectively, whenµ=2, are 120 KHz, 14, 80 and 8, respectively, when µ=3, or are 240 KHz,14, 160 and 16, respectively, when µ=4. Meanwhile, in a case where anextended CP is used, SCS (=15*2^(µ)), N^(slot) _(symb), _(N) ^(frame,µ)and N^(subframe,µ) are 60 KHz, 12, 40 and 2, respectively, when µ=2.

In an NR system, OFDM(A) numerologies (e.g., SCS, CP length, and so on)between multiple cells being integrate to one UE may be differentlyconfigured. Accordingly, a (absolute time) duration (or section) of atime resource (e.g., subframe, slot or TTI) (collectively referred to asa time unit (TU) for simplicity) being configured of the same number ofsymbols may be differently configured in the integrated cells. In theNR, multiple numerologies or SCSs for supporting diverse 5G services maybe supported. For example, in case an SCS is 15 kHz, a wide area of theconventional cellular bands may be supported, and, in case an SCS is 30kHz/60 kHz a dense-urban, lower latency, wider carrier bandwidth may besupported. In case the SCS is 60 kHz or higher, a bandwidth that isgreater than 24.25 GHz may be used in order to overcome phase noise.

An NR frequency band may be defined as two different types of frequencyranges. The two different types of frequency ranges may be FR1 and FR2.The values of the frequency ranges may be changed (or varied), and, forexample, frequency ranges corresponding to the FR1 and FR2 may be 450MHz-6000 MHz and 24250 MHz-52600 MHz, respectively. Further, supportableSCSs is 15, 30 and 60 kHz for the FR1 and 60, 120, 240 kHz for the FR2.Among the frequency ranges that are used in an NR system, FR1 may mean a“sub 6 GHz range”, and FR2 may mean an “above 6 GHz range” and may alsobe referred to as a millimeter wave (mmW).

As described above, the values of the frequency ranges in the NR systemmay be changed (or varied). For example, comparing to examples for thefrequency ranges described above, FR1 may be defined to include a bandwithin a range of 410 MHz to 7125 MHz. More specifically, FR1 mayinclude a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, and so on)and higher. For example, a frequency band of 6 GHz (or 5850, 5900, 5925MHz, and so on) and higher being included in FR1 mat include anunlicensed band. The unlicensed band may be used for diverse purposes,e.g., the unlicensed band for vehicle-specific communication (e.g.,automated driving).

FIG. 5 illustrates a structure of a slot of an NR frame, in accordancewith an embodiment of the present disclosure. The embodiment of FIG. 5may be combined with various embodiments of the present disclosure.

Referring to FIG. 5 , a slot includes a plurality of symbols in a timedomain. For example, in case of a normal CP, one slot may include 14symbols. However, in case of an extended CP, one slot may include 12symbols. Alternatively, in case of a normal CP, one slot may include 7symbols. However, in case of an extended CP, one slot may include 6symbols.

A carrier includes a plurality of subcarriers in a frequency domain. AResource Block (RB) may be defined as a plurality of consecutivesubcarriers (e.g., 12 subcarriers) in the frequency domain. A BandwidthPart (BWP) may be defined as a plurality of consecutive (Physical)Resource Blocks ((P)RBs) in the frequency domain, and the BWP maycorrespond to one numerology (e.g., SCS, CP length, and so on). Acarrier may include a maximum of N number BWPs (e.g., 5 BWPs). Datacommunication may be performed via an activated BWP. Each element may bereferred to as a Resource Element (RE) within a resource grid and onecomplex symbol may be mapped to each element.

Meanwhile, a radio interface between a UE and another UE or a radiointerface between the UE and a network may consist of an L1 layer, an L2layer, and an L3 layer. In various embodiments of the presentdisclosure, the L1 layer may imply a physical layer. In addition, forexample, the L2 layer may imply at least one of a MAC layer, an RLClayer, a PDCP layer, and an SDAP layer. In addition, for example, the L3layer may imply an RRC layer.

Bandwidth Part (BWP)

The BWP may be a set of consecutive physical resource blocks (PRBs) in agiven numerology. The PRB may be selected from consecutive sub-sets ofcommon resource blocks (CRBs) for the given numerology on a givencarrier.

When using bandwidth adaptation (BA), a reception bandwidth andtransmission bandwidth of a UE are not necessarily as large as abandwidth of a cell, and the reception bandwidth and transmissionbandwidth of the BS may be adjusted. For example, a network/BS mayinform the UE of bandwidth adjustment. For example, the UE receiveinformation/configuration for bandwidth adjustment from the network/BS.In this case, the UE may perform bandwidth adjustment based on thereceived information/configuration. For example, the bandwidthadjustment may include an increase/decrease of the bandwidth, a positionchange of the bandwidth, or a change in subcarrier spacing of thebandwidth.

For example, the bandwidth may be decreased during a period in whichactivity is low to save power. For example, the position of thebandwidth may move in a frequency domain. For example, the position ofthe bandwidth may move in the frequency domain to increase schedulingflexibility. For example, the subcarrier spacing of the bandwidth may bechanged. For example, the subcarrier spacing of the bandwidth may bechanged to allow a different service. A subset of a total cell bandwidthof a cell may be called a bandwidth part (BWP). The BA may be performedwhen the BS/network configures the BWP to the UE and the BS/networkinforms the UE of the BWP currently in an active state among theconfigured BWPs.

For example, the BWP may be at least any one of an active BWP, aninitial BWP, and/or a default BWP. For example, the UE may not monitordownlink radio link quality in a DL BWP other than an active DL BWP on aprimary cell (PCell). For example, the UE may not receive PDCCH, PDSCH,or CSI-RS (excluding RRM) outside the active DL BWP. For example, the UEmay not trigger a channel state information (CSI) report for theinactive DL BWP. For example, the UE may not transmit a Physical UplinkControl Channel (PUCCH) or a Physical Uplink Shared Channel (PUSCH)outside an active UL BWP. For example, in a downlink case, the initialBWP may be given as a consecutive RB set for a remaining minimum systeminformation (RMSI) control resource set (CORESET) (configured by PBCH).For example, in an uplink case, the initial BWP may be given by systeminformation block (SIB) for a random access procedure. For example, thedefault BWP may be configured by a higher layer. For example, an initialvalue of the default BWP may be an initial DL BWP. For energy saving, ifthe UE fails to detect downlink control information (DCI) during aspecific period, the UE may switch the active BWP of the UE to thedefault BWP.

Meanwhile, the BWP may be defined for SL. The same SL BWP may be used intransmission and reception. For example, a transmitting UE may transmitan SL channel or an SL signal on a specific BWP, and a receiving UE mayreceive the SL channel or the SL signal on the specific BWP. In alicensed carrier, the SL BWP may be defined separately from a Uu BWP,and the SL BWP may have configuration signaling separate from the UuBWP. For example, the UE may receive a configuration for the SL BWP fromthe BS/network. The SL BWP may be (pre-)configured in a carrier withrespect to an out-of-coverage NR V2X UE and an RRC_IDLE UE. For the UEin the RRC_CONNECTED mode, at least one SL BWP may be activated in thecarrier.

FIG. 6 illustrates an example of a BWP, in accordance with an embodimentof the present disclosure. The embodiment of FIG. 6 may be combined withvarious embodiments of the present disclosure. It is assumed in theembodiment of FIG. 6 that the number of BWPs is 3.

Referring to FIG. 6 , a common resource block (CRB) may be a carrierresource block numbered from one end of a carrier band to the other endthereof. In addition, the PRB may be a resource block numbered withineach BWP. A point A may indicate a common reference point for a resourceblock grid.

The BWP may be configured by a point A, an offset (N^(start) _(BWP))from the point A, and a bandwidth (N^(size) _(BWP)). For example, thepoint A may be an external reference point of a PRB of a carrier inwhich a subcarrier 0 of all numerologies (e.g., all numerologiessupported by a network on that carrier) is aligned. For example, theoffset may be a PRB interval between a lowest subcarrier and the point Ain a given numerology. For example, the bandwidth may be the number ofPRBs in the given numerology.

V2X or Sidelink Communication

FIGS. 7A and 7B illustrate a radio protocol architecture for a SLcommunication, in accordance with an embodiment of the presentdisclosure. The embodiment of FIGS. 7A and 7B may be combined withvarious embodiments of the present disclosure. More specifically, FIG.7A exemplifies a user plane protocol stack, and FIG. 7B exemplifies acontrol plane protocol stack.

Sidelink Synchronization Signal (SLSS) And Synchronization Informaion

The SLSS may include a primary sidelink synchronization signal (PSSS)and a secondary sidelink synchronization signal (SSSS), as anSL-specific sequence. The PSSS may be referred to as a sidelink primarysynchronization signal (S-PSS), and the SSSS may be referred to as asidelink secondary synchronization signal (S-SSS). For example,length-127 M-sequences may be used for the S-PSS, and length-127 goldsequences may be used for the S-SSS. For example, a UE may use the S-PSSfor initial signal detection and for synchronization acquisition. Forexample, the UE may use the S-PSS and the S-SSS for acquisition ofdetailed synchronization and for detection of a synchronization signalID.

A physical sidelink broadcast channel (PSBCH) may be a (broadcast)channel for transmitting default (system) information which must befirst known by the UE before SL signal transmission/reception. Forexample, the default information may be information related to SLSS, aduplex mode (DM), a time division duplex (TDD) uplink/downlink (UL/DL)configuration, information related to a resource pool, a type of anapplication related to the SLSS, a subframe offset, broadcastinformation, or the like. For example, for evaluation of PSBCHperformance, in NR V2X, a payload size of the PSBCH may be 56 bitsincluding 24-bit CRC.

The S-PSS, the S-SSS, and the PSBCH may be included in a block format(e.g., SL synchronization signal (SS)/PSBCH block, hereinafter,sidelink-synchronization signal block (S-SSB)) supporting periodicaltransmission. The S-SSB may have the same numerology (i.e., SCS and CPlength) as a physical sidelink control channel (PSCCH)/physical sidelinkshared channel (PSSCH) in a carrier, and a transmission bandwidth mayexist within a (pre-) configured sidelink (SL) BWP. For example, theS-SSB may have a bandwidth of 11 resource blocks (RBs). For example, thePSBCH may exist across 11 RBs. In addition, a frequency position of theS-SSB may be (pre-)configured. Accordingly, the UE does not have toperform hypothesis detection at frequency to discover the S-SSB in thecarrier.

For example, based on Table 1, the UE may generate an S-SS/PSBCH block(i.e., S-SSB), and the UE may transmit the S-SS/PSBCH block (i.e.,S-SSB) by mapping it on a physical resource.

TABLE 1 ■ Time-frequency structure of an S-SS/PSBCH block In the timedomain, an S-SS/PSBCH block consists of N_(symb)^(S ⋅ SSB) OFDM symbols,numbered in increasing order from 0 to N_(symb)^(S−SSB) − 1 within theS-SS/PSBCH block, where S-PSS, S-SSS, and PSBCH with associated DM-RSare mapped to symbols as given by Table 8.4.3.1-1. The number of OFDMsymbols in an S-SS/PSBCH block N_(symb)^(S−SSB) = 13 for normal cyclicprefix and N_(symb)^(S−SSB) = 11 for extended cyclic prefix. The firstOPDM symbol in an S-SS/PSBCH block is the first OPDM symbol in the slot.In the frequency domain, an S-SS/PSBCH block consists of 132 contiguoussubcarriers with the subcarriers numbered in increasing order from 0 to131 within the sidelink S-SS/PSBCH block. The quantities k and lrepresent the frequency and time indices, respectively, within onesidelink S-SS/PSBCH block. and DM-RS for PSBCH, For an S-SS/PSBCH block,the UE shall use - antenna port 4000 for transmission of S-PSS. S-SSS,PSBCH and DM-RS for PSBCH: - the same cyclic prefix length andsubcarrier spacing for the S-PSS, S-SSS, PSBCH Table 8.4.3.1-1:Resources within an S-SS/PSBCH block for S-PSS, S-SS, PSBCH, and DM-RS.

Synchroniztion Acquistion of SL Terminal

In TDMA and FDMA systems, accurate time and frequency synchronization isessential. Inaccurate time and frequency synchronization may lead todegradation of system performance due to inter-symbol interference (ISI)and inter-carrier interference (ICI). The same is true for V2X. Fortime/frequency synchronization in V2X, a sidelink synchronization signal(SLSS) may be used in the PHY layer, and master informationblock-sidelink-VX (MIB-SL-V2X) may be used in the RLC layer.

FIG. 8 illustrates a synchronization source or synchronization referenceof V2X, in accordance with an embodiment of the present disclosure. Theembodiment of FIG. 8 may be combined with various embodiments of thepresent disclosure.

Referring to FIG. 8 , in V2X, a UE may be synchronized with a GNSSdirectly or indirectly through a UE (within or out of network coverage)directly synchronized with the GNSS. When the GNSS is configured as asynchronization source, the UE may calculate a direct subframe number(DFN) and a subframe number by using a coordinated universal time (UTC)and a (pre)determined DFN offset.

Alternatively, the UE may be synchronized with a BS directly or withanother UE which has been time/frequency synchronized with the BS. Forexample, the BS may be an eNB or a gNB. For example, when the UE is innetwork coverage, the UE may receive synchronization informationprovided by the BS and may be directly synchronized with the BS.Thereafter, the UE may provide synchronization information to anotherneighboring UE. When a BS timing is set as a synchronization reference,the UE may follow a cell associated with a corresponding frequency (whenwithin the cell coverage in the frequency), a primary cell, or a servingcell (when out of cell coverage in the frequency), for synchronizationand DL measurement.

The BS (e.g., serving cell) may provide a synchronization configurationfor a carrier used for V2X or SL communication. In this case, the UE mayfollow the synchronization configuration received from the BS. When theUE fails in detecting any cell in the carrier used for the V2X or SLcommunication and receiving the synchronization configuration from theserving cell, the UE may follow a predetermined synchronizationconfiguration.

Alternatively, the UE may be synchronized with another UE which has notobtained synchronization information directly or indirectly from the BSor GNSS. A synchronization source and a preference may be preset for theUE. Alternatively, the synchronization source and the preference may beconfigured for the UE by a control message provided by the BS.

An SL synchronization source may be related to a synchronizationpriority. For example, the relationship between synchronization sourcesand synchronization priorities may be defined as shown in [Table 2] or[Table 3]. [Table 2] or [Table 3] is merely an example, and therelationship between synchronization sources and synchronizationpriorities may be defined in various manners.

TABLE 2 Priority Level GNSS-based synchronization eNB/gNB-basedsynchronization P0 GNSS eNB/gNB P1 All UEs synchronized All UEssynchronized directly with directly with GNSS NB/gNB P2 All UEssynchronized indirectly with GNSS All UEs synchronized indirectly witheNB/gNB P3 All other UEs GNSS P4 N/A All UEs synchronized directly withGNSS P5 N/A All UEs synchronized indirectly with GNSS P6 N/A All otherUEs

TABLE 3 Priority Level GNSS-based synchronization eNB/gNB-basedsynchronization P0 GNSS eNB/gNB P1 All UEs synchronized directly withGNSS All UEs synchronized directly with eNB/gNB P2 All UEs synchronizedindirectly with GNSS All UEs synchronized indirectly with eNB/gNB P3eNB/gNB GNSS P4 All UEs synchronized directly with eNB/gNB All UEssynchronized directly with GNSS P5 All UEs synchronized indirectly witheNB/gNB All UEs synchronized indirectly with GNSS P6 Remaining UE(s)with lower priority Remaining UE(s) with lower priority

In [Table 2] or [Table 3], P0 may represent a highest priority, and P6may represent a lowest priority. In [Table 2] or [Table 3], the BS mayinclude at least one of a gNB or an eNB.

Whether to use GNSS-based synchronization or eNB/gNB- basedsynchronization may be (pre)determined. In a single-carrier operation,the UE may derive its transmission timing from an availablesynchronization reference with the highest priority.

For example, the UE may (re)select a synchronization reference, and theUE may obtain synchronization from the synchronization reference. Inaddition, the UE may perform SL communication (e.g., PSCCH/PSSCHtransmission/reception, physical sidelink feedback channel (PSFCH)transmission/reception, S-SSB transmission/reception, reference signaltransmission/reception, etc.) based on the obtained synchronization.

FIGS. 9A and 9B illustrate a procedure of performing V2X or SLcommunication by a terminal based on a transmission mode, in accordancewith an embodiment of the present disclosure. The embodiment of FIGS. 9Aand 9B may be combined with various embodiments of the presentdisclosure. In various embodiments of the present disclosure, thetransmission mode may be called a mode or a resource allocation mode.Hereinafter, for convenience of explanation, in LTE, the transmissionmode may be called an LTE transmission mode. In NR, the transmissionmode may be called an NR resource allocation mode.

For example, FIG. 9A exemplifies a UE operation related to an LTEtransmission mode 1 or an LTE transmission mode 3. Alternatively, forexample, FIG. 9B exemplifies a UE operation related to an NR resourceallocation mode 1. For example, the LTE transmission mode 1 may beapplied to general SL communication, and the LTE transmission mode 3 maybe applied to V2X communication.

For example, FIG. 9B exemplifies a UE operation related to an LTEtransmission mode 2 or an LTE transmission mode 4. Alternatively, forexample, FIG. 9A exemplifies a UE operation related to an NR resourceallocation mode 2.

Referring to FIG. 9A, in the LTE transmission mode 1, the LTEtransmission mode 3, or the NR resource allocation mode 1, a BS mayschedule an SL resource to be used by the UE for SL transmission. Forexample, a base station may transmit information related to SLresource(s) and/or information related to UL resource(s) to a first UE.For example, the UL resource(s) may include PUCCH resource(s) and/orPUSCH resource(s). For example, the UL resource(s) may be resource(s)for reporting SL HARQ feedback to the base station.

For example, the first UE may receive information related to dynamicgrant (DG) resource(s) and/or information related to configured grant(CG) resource(s) from the base station. For example, the CG resource(s)may include CG type 1 resource(s) or CG type 2 resource(s). In thepresent disclosure, the DG resource(s) may be resource(s)configured/allocated by the base station to the first UE through adownlink control information (DCI). In the present disclosure, the CGresource(s) may be (periodic) resource(s) configured/allocated by thebase station to the first UE through a DCI and/or an RRC message. Forexample, in the case of the CG type 1 resource(s), the base station maytransmit an RRC message including information related to CG resource(s)to the first UE. For example, in the case of the CG type 2 resource(s),the base station may transmit an RRC message including informationrelated to CG resource(s) to the first UE, and the base station maytransmit a DCI related to activation or release of the CG resource(s) tothe first UE.

Subsequently, the first UE may transmit a PSCCH (e.g., sidelink controlinformation (SCI) or 1^(st)-stage SCI) to a second UE based on theresource scheduling. After then, the first UE may transmit a PSSCH(e.g., 2^(nd)-stage SCI, MAC PDU, data, etc.) related to the PSCCH tothe second UE. After then, the first UE may receive a PSFCH related tothe PSCCH/PSSCH from the second UE. For example, HARQ feedbackinformation (e.g., NACK information or ACK information) may be receivedfrom the second UE through the PSFCH. After then, the first UE maytransmit/report HARQ feedback information to the base station throughthe PUCCH or the PUSCH. For example, the HARQ feedback informationreported to the base station may be information generated by the firstUE based on the HARQ feedback information received from the second UE.For example, the HARQ feedback information reported to the base stationmay be information generated by the first UE based on a pre-configuredrule. For example, the DCI may be a DCI for SL scheduling. For example,a format of the DCI may be a DCI format 3_0 or a DCI format 3_1. Table 4shows an example of a DCI for SL scheduling.

TABLE 4 3GPP TS 38.212 ■ Format 3_0 DCI format 3_0 is used forscheduling of NR PSCCH and NR PSSCH in one cell. The followinginformation is transmitted by means of the DCI format 3_0 with CRCscrambled by SL-RNTI or SL-CS-RNTI: – Resource pool index -[log₂I] bits,where I is the number of resource pools for transmission configured bythe higher layer parameter sl-TxPoolScheduling. – Time gap - 3 bitsdetermined by higher layer parameter sl-DCI-ToSL-Trans, as defined inclause 8.1.2.1 of [6, TS 38.214] – HARQ process number - 4 bits asdefined in clause 16.4 of [5, TS 38.213] – New data indicator - 1 bit asdefined in clause 16.4 of [5, TS 38.213] – Lowest index of thesubchannel allocation to the initial transmission−⌈log₂(N_(subChannel)^(SL))⌉ bits as defined in clause 8.1.2.2 of [6, TS38.214] – SCI format 1-A fields according to clause 8.3.1.1: – Frequencyresource assignment. – Time resource assignment. – PSFCH-to-HARQfeedback timing indicator -[log₂N_(fb_timing)] bits, where N_(fb­_timing)is the number of entries in the higher layer parameter sl-PSFCH-ToPUCCH,as defined in clause 16.5 of [5, TS 38.213] pdsch-HARQ-ACK-Codebook =dynamic pdsch-HARQ-ACK-Codebook = semi-static – PUCCH resourceindicator - 3 bits as defined in clause 16.5 of [5, TS 38.213]. –Configuration index - 0 bit if the UE is not configured to monitor DCIformat 3_0 with CRC scrambled by SL-CS-RNTI: otherwise 3 bits as definedin clause 8.1.2 of [6, TS 38.214]. If the UE is configured to monitorDCI format 3_0 with CRC scrambled by SL-CS-RNTI, this field is reservedfor DCI format 3_0 with CRC scrambled by SL-RNTI. – Counter sidelinkassignment index - 2 bits – 2 bits as defined in clause 16.5.2 of [5, TS38.213] if the UE is configured with – 2 bits as defined in clause16.5.1 of [5, TS 38.213] if the UE is configured with – Padding bits, ifrequired ■ Format 3_1 DCI format 3_1 is used for scheduling of LTE PSCCHand LTE PSSCH in one cell. The following information is transmitted bymeans of the DCI format 3_1 with CRC scramb by SL-L-CS-RNTI: – Timingoffset - 3 bits determined by higher layer parameter sl-TimeOffsetEUTRA,defined in clause 16.6 of [5, TS 38.213] – Carrier indicator -3 bits asdefined in 5.3.3.1.9A of [11, TS 36.212]. – Lowest index of thesubchannel allocation to the initial transmission –⌈log₂(N_(subchannel)^(SL))⌉ bits as defined in 5.3.3.1.9A of [11, TS36.212]. – Time gap between initial transmission and retransmission, asdefined in 5.3.3.1.9A [11, TS 36.212] – SL index - 2 bits as defined in5.3.3.1.9A of [11, TS 36.212] – Frequency resource location of initialtransmission and retransmission, as defined 5.3.3.1.9A of [11, TS36.212] – SL SPS configuration index - 3 bits as defined in clause5.3.3.1.9A of [11, TS 36.21 – Activation/release indication - 1 bit asdefined in clause 5.3.3.1.9A of [11, 36.212].

Referring to FIG. 9B, in the LTE transmission mode 2, the LTEtransmission mode 4, or the NR resource allocation mode 2, the UE maydetermine an SL transmission resource within an SL resource configuredby a BS/network or a pre-configured SL resource. For example, theconfigured SL resource or the pre-configured SL resource may be aresource pool. For example, the UE may autonomously select or schedule aresource for SL transmission. For example, the UE may perform SLcommunication by autonomously selecting a resource within a configuredresource pool. For example, the UE may autonomously select a resourcewithin a selective window by performing a sensing and resource(re)selection procedure. For example, the sensing may be performed inunit of subchannel(s). For example, subsequently, a first UE which hasselected resource(s) from a resource pool by itself may transmit a PSCCH(e.g., sidelink control information (SCI) or 1^(st)-stage SCI) to asecond UE by using the resource(s). After then, the first UE maytransmit a PSSCH (e.g., 2^(nd)-stage SCI, MAC PDU, data, etc.) relatedto the PSCCH to the second UE. In step S8030, the first UE may receive aPSFCH related to the PSCCH/PSSCH from the second UE.

Referring to FIGS. 9A and 9B, for example, the first UE may transmit aSCI to the second UE through the PSCCH. Alternatively, for example, thefirst UE may transmit two consecutive SCIs (e.g., 2-stage SCI) to thesecond UE through the PSCCH and/or the PSSCH. In this case, the secondUE may decode two consecutive SCIs (e.g., 2-stage SCI) to receive thePSSCH from the first UE. In the present disclosure, a SCI transmittedthrough a PSCCH may be referred to as a 1^(st) SCI, a first SCI, a1^(st)-stage SCI or a 1^(st)-stage SCI format, and a SCI transmittedthrough a PSSCH may be referred to as a 2^(nd) SCI, a second SCI, a2^(nd)-stage SCI or a 2^(nd)-stage SCI format. For example, the1^(st)-stage SCI format may include a SCI format 1-A, and the2^(nd)-stage SCI format may include a SCI format 2-A and/or a SCI format2-B. Table 5 shows an example of a 1^(st)-stage SCI format.

TABLE 5 3GPP TS 38.212 ■ SCI format 1-A SCI format 1-A is used for thescheduling of PSSCH and 2^(nd)-stage-SCI on PSSCH TS 38.214]. Thefollowing information is transmitted by means of the SCI format 1-A: –Priority - 3 bits as specified in clause 5.4.3.3 of [12. TS 23.287] andclause 5.22.1.3.1 of [8, TS 38.321]. – Frequency resource assignment$- \left\lceil {\log_{2}\left( \frac{N_{\text{subChannel}}^{\text{SL}}\left( {N_{\text{subChannel}}^{\text{SL}} + 1} \right)}{2} \right)} \right\rceil$bits when the value of the higher layer parameter sl-MaxNumPerReserve isconfigured to 2; otherwise$\left\lceil {\log_{2}\left( \frac{N_{\text{subChannel}}^{\text{SL}}\left( {N_{\text{subChannel}}^{\text{SL}} + 1} \right)\left( {2N_{\text{subChannel}}^{\text{SL}} + 1} \right)}{5} \right)} \right\rceil$bits when the value of the higher layer parameter sl-MaxNumPerReserve isconfigured to 3, as defined in clause 8.1.2.2 of [6, – Time resourceassignment - 5 bits when the value of the higher layer parametersl-MaxNumPerReserve is configured to 2: otherwise 9 bits when the valueof the higher layer parameter sl-MaxNumPerReserve is configured to 3, asdefined in clause 3.1.2.1 of [6, TS 38.214]. – Resource reservationperiod -[log₂ N_(rsv_period)] bits as defined in clause 8.1.4 of [6, TS38.214], where N_(rsv_period) is the number of entries in the higherlayer parameter sl-ResourceReservePeriodList, if higher layer parametersl-MultiReserveResource is configured; 0 bit otherwise. – DMRS pattern -[log₂ N_(pattern)] bits as defined in clause 8.4.1.1.2 of [4, TS38.211]. where N_(pattern) is the number of DMRS patterns configured byhigher layer parameter sl-PSSCH-DMRS-TimePatternList. – 2^(nd)-stage SCIformat - 2 bits as defined in Table 8.3.1.1-1. – Beta_offset indicator -2 bits as provided by higher layer parameter sl-BetaOffsets2ndSCI andTable 8.3.1.1-2. – Number of DMRS port - 1 bit as defined in Table8.3.1.1-3. – Modulation and coding scheme - 5 bits as defined in clause8.1.3 of [6, TS 38.214]. – Additional MCS table indicator - as definedin clause 8.1.3.1 of [6, TS 38.214]: 1 bit if one MCS table isconfigured by higher layer parameter sl-Additional-MCS-Table: 2 bits iftwo MCS tables are configured by higher layer parameter sl-Additional-MCS-Table; 0 bit otherwise. – PSFCH overhead indication - 1bit as defined clause 8.1.3.2 of [6, TS 38.214] if higher layerparameter sl-PSFCH-Period = 2 or 4; 0 bit otherwise. – Reserved - anumber of bits as determined by higher layer parametersl-NumReservedBits, with value set to zero. Table 8.3.1.1-1:2^(nd)-stage SCI formats

Table 8.3.1.1-2: Mapping of Beta_offset indicator values to indexes inTable 9.3-2 of [5, TS38.213]

Table 6 shows an example of a 2^(nd)-stage SCI format.

TABLE 6 3GPP TS 38.212 ■ SCI format 2-A SCI format 2-A is used for thedecoding of PSSCH, with HARQ operation when HARQ-ACK informationincludes ACK or NACK, when HARQ-ACK information includes only NACK, orwhen there is no feedback of HARQ-ACK information. The followinginformation is transmitted by means of the SCI format 2-A: – HARQprocess number - 4 bits as defined in clause 16.4 of [5, TS 38.213]. –New data indicator - 1 bit as defined in clause 16.4 of [5, TS 38.213].– Redundancy version - 2 bits as defined in clause 16.4 of [6, TS38.214]. – Source ID - 8 bits as defined in clause 8.1 of [6, TS38.214]. – Destination ID - 16 bits as defined in clause 8.1 of [6, TS28.214]. – HARQ feedback enabled/disabled indicator - 1 bit as definedin clause 16.3 of [5, TS 38.213]. – Cast type indicator- 2 bits asdefined in Table 8.4.1.1-1. – CSI request - 1 bit as defined in clause8.2.1 of [6, TS 38.214]. Table 8.4.1.1-1: Cast type indicator

■ SCI format 2-B SCI format 2-B is used for the decoding of PSSCH, withHARQ operation when HARQ-ACK information includes only NACK, or whenthere is no feedback of HARQ-ACK information. The following informationis transmitted by means of the SCI format 2-B: – HARQ process number - 4bits as defined in clause 16.4 of [5, TS 38.213]. – New data indicator -1 bit as defined in clause 16.4 of [5, TS 38.213]. – Redundancy version-2 bits as defined in clause 16.4 of [6, TS 38.214]. – Source ID - 8 bitsas defined in clause 8.1 of [6, TS 38.214]. – Destination ID - 16 bitsas defined in clause 8.1 of [6, TS 38.214]. – HARQ feedbackenabled/disabled indicator - 1 bit as defined in clause 16.3 of [5, TS38.213]. – Zone ID - 12 bits as defined in clause 5.8.11 of [9, TS38.331]. – Communication range requirement - 4 bits determined by higherlayer parameter sl-ZoneConfigMCR-index.

Referring to FIGS. 9A and 9B, the first UE may receive the PSFCH basedon Table 7. For example, the first UE and the second UE may determine aPSFCH resource based on Table 7, and the second UE may transmit HARQfeedback to the first UE using the PSFCH resource.

TABLE 7 3GPP TS 38.213 ■ UE procedure for reporting HARQ-ACK on sidelinkA UE can be indicated by an SCI format scheduling a PSSCH reception, inone or more sub-channels from a number of N_(subch)^(PSSCH) sub-channelsto transmit a PSFCH with HARQ-ACK information in response to the PSSCHreception. The UE provides HARQ-ACK information that includes ACK orNACK, or only NACK. A UE can be provided, by sl-PSFCH-Period-r16, anumber of slots in a resource pool for a period of PSFCH transmissionoccasion resources. If the number is zero, PSFCH transmissions from theUE in the resource pool are disabled. A UE expects that a slott^(′)_( k)^(SL) (0 ≤ k < T′_(max)) has a PSFCH transmission occasionresource if k mod N_(PSSCH)^(PSFCH) = 0. where t^(′)_( k)^(SL) isdefined in [6, TS 38.214], and T′_(max) is a number of slots that belongto the resource pool within 10240 msec according to [6, TS 38.214], andN_(PSSCH)^(PSFCH) is provided by sl-PSFCH-Period-r16. A UE may beindicated by higher layers to not transmit a PSFCH in response to aPSSCH reception [11, TS 38.321]. If a UE receives a PSSCH in a resourcepool and the HARQ feedback enabled/disabled indicator field in anassociated SCI format 2-A or a SCI format 2-B has value 1 [5, TS38.212]. the UE provides the HARQ-ACK information in a PSFCHtransmission in the resource pool. The UE transmits the PSFCH in a firstslot that includes PSFCH resources and is at least a number of slots,provided by sl-MinTimeGapPSFCH-r16, of the resource pool after a lastslot of the PSSCH reception. A UE is provided by sl-PSFCH-RB-Set-r16 aset of M_(PRB, set)^(PSFCH) PRBs in a resource pool for PSFCHtransmission in a PRB of the resource pool. For a number of N_(subch)sub-channels for the resource pool, provided by sl-NumSubchannel, and anumber of PSSCH slots associated with a PSFCH slot that is less than orequal to N_(PSSCH)^(PSFCH), the UE allocates the[(i + j ⋅ N_(PSSCH)^(PSPCH)) ⋅ M_(subch, slot)^(PSFCH), (i + 1 + j ⋅ N_(PSSCH)^(PSFCH)) ⋅ M_(subch, slot)^(PSFCH) − 1]PRBs from the M_(PRB, set)^(PSFCH) PRBs to slot i among the PSSCH slotsassociated with the PSFCH slot and sub-channel j, where and theallocation starts in an ascending order of i and continues in anascending order of j. The UE expects that is a multiple of N_(subch)N_(PSSCH)^(PSFCH), A UE determines a number of PSFCH resources availablefor multiplexing HARQ-ACK information in a PSFCH transmission asR_(PRB, CS)^(PSFCH) = N_(type)^(PSFCH) ⋅ M_(subch,  slot)^(PSFCH) ⋅ N_(CS)^(PSFCH)where N_(CS)^(PSFCH) is a number of cyclic shift pairs for the resourcepool and, based on an indication by higher layers, –N_(type)^(PSFCH) = 1. and the M_(subch, slot)^(PSFCH) PRBs areassociated with the starting sub-channel of the corresponding PSSCH –N_(type)^(PSFCH) = N_(subch)^(PSSCH) and theN_(subch)^(PSSCH) ⋅ M_(subch. slot)^(PSFCH) PRBs are associated with oneor more sub-channels from the N_(subch)^(PSSCH) sub-channels of thecorresponding PSSCH The PSFCH resources are first indexed according toan ascending order of the PRB index, from theN_(type)^(PSFCH) ⋅ M_(subch, slot)^(PSFCH) PRBs, and then according toan ascending order of the cyclic shift pair index from theN_(CS)^(PSFCH) cyclic shift pairs. A UE determines an index of a PSFCHresource for a PSFCH transmission in response to a PSSCH reception as(P_(ID) + M_(ID))modR_(PRB, CS)^(PSFCH) where P_(ID) is a physical layersource ID provided by SCI format 2-A or 2-B [5, TS 38.212] schedulingthe PSSCH reception, and M_(ID) is the identity of the UE receiving thePSSCH as indicated by higher layers if the UE detects a SCI format 2-Awith Cast type indicator field value of “01”; otherwise, M_(ID) is zero.A UE determines a m₀ value, for computing a value of cyclic shift a [4.TS 38.211], from a cyclic shift pair index corresponding to a PSFCHresource index and from N_(CS)^(PSFCH) using Table 16.3-1.

Table 16.3-1: Set of cyclic shift pairs A UE determines a m_(cs) value,for computing a value of cyclic shift a [4, TS 38.211], as in Table16.3-2 if the UE detects a SCI format 2-A with Cast type indicator fieldvalue of “01” or “10°, or as in Table 16.3-3 if the UE detects a SCIformat 2-B or a SCI format 2-A with Cast type indicator field value of“11”. The UE applies one cyclic shift from a cyclic shift pair to asequence used for the PSFCH transmission [4, TS 38.211]. Table 16.3-2:Mapping of HARQ-ACK information bit values to a cyclic shift, from acyclic shift pair, of a sequence for a PSFCH transmission when HARQ-ACKinformation includes ACK or NACK HARQ-ACK Value 0 (NACK) 1 (ACK)Sequence cyclic shift 0 8 Table 16.3-3: Mapping of HARQ-ACK informationbit values to a cyclic shift from a cyclic shift pair, of a sequence fora PSFCH transmission when HARQ-ACK information includes only NACK

Referring to FIG. 9A, the first UE may transmit SL HARQ feedback to thebase station through the PUCCH and/or the PUSCH based on Table 8.

TABLE 8 3GPP TS 38.213 16.5 UE procedure for reporting HARQ-ACK onuplink A UE can be provided PUCCH resources or PUSCH resources [12, TS38.331] to report HARQ-ACK information that the UE generates based onHARQ-ACK information that the UE obtains from PSFCH receptions, or fromabsence of PSFCH receptions. The UE reports HARQ-ACK information on theprimary cell of the PUCCH group, as described in Clause 9, of the cellwhere the UE monitors PDCCH for detection of DCI format 3_0. For SLconfigured grant Type 1 or Type 2 PSSCH transmissions by a UE within atime period provided by sl-PeriodCG, the UE generates one HARQ-ACKinformation bit in response to the PSFCH receptions to multiplex in aPUCCH transmission occasion that is after a last time resource, in a setof time resources. For PSSCH transmissions scheduled by a DCI format3_0, a UE generates HARQ-ACK information in response to PSFCH receptionsto multiplex in a PUCCH transmission occasion that is after a last timeresource in a set of time resources provided by the DCI format 3_0. Foreach PSFCH reception occasion, from a number of PSFCH receptionoccasions, the UE generates HARQ-ACK information to report in a PUCCH orPUSCH transmission. The UE can be indicated by a SCI format to performone of the following and the UE constructs a HARQ-ACK codeword withHARQ-ACK information, when applicable – if the UE receives a PSFCHassociated with a SCI format 2-A with Cast type indicator field value of“10” – generate HARQ-ACK information with same value as a value ofHARQ-ACK information the UE determines from a PSFCH reception in thePSFCH reception occasion and, if the UE determines that a PSFCH is notreceived at the PSFCH reception occasion, generate NACK – if the UEreceives a PSFCH associated with a SCI format 2-A with Cast typeindicator field value of “01” – generate ACK if the UE determines ACKfrom at least one PSFCH reception occasion, from the number of PSFCHreception occasions, in PSFCH resources corresponding to every identityM_(ID) of the UEs that the UE expects to receive the PSSCH as describedin Clause 16.3: otherwise, generate NACK – if the UE receives a PSFCHassociated with a SCI format 2-B or a SCI format 2-A with Cast typeindicator field value of “11” – generate ACK when the UE determinesabsence of PSFCH reception for each PSFCH reception occasion from thenumber of PSFCH reception occasions; otherwise, generate NACK After a UEtransmits PSSCHs and receives PSFCHs in corresponding PSFCH resourceoccasions, the priority value of HARQ-ACK information is same as thepriority value of the PSSCH transmissions that is associated with thePSFCH reception occasions providing the HARQ-ACK information. The UEgenerates a NACK when, due to prioritization, as described in Clause16.2.4, the UE does not receive PSFCH in any PSFCH reception occasionassociated with a PSSCH transmission in a resource provided by a DCIformat 3_0 with CRC scrambled by a SL-RNTI or, for a configured grant,in a resource provided in a single period and for which the UE isprovided a PUCCH resource to report HARQ-ACK information. The priorityvalue of the NACK is same as the priority value of the PSSCHtransmission. The UE generates a NACK when, due to prioritization asdescribed in Clause 16.2.4, the UE does not transmit a PSSCH in any ofthe resources provided by a DCI format 3_0 with CRC scrambled by SL-RNTIor, for a configured grant, in any of the resources provided in a singleperiod and for which the UE is provided a PUCCH resource to reportHARQ-ACK information. The priority value of the NACK is same as thepriority value of the PSSCH that was not transmitted due toprioritization. The UE generates an ACK if the UE does not transmit aPSCCH with a SCI format 1-A scheduling a PSSCH in any of the resourcesprovided by a configured grant in a single period and for which the UEis provided a PUCCH resource to report HARQ-ACK information. Thepriority value of the ACK is same as the largest priority value amongthe possible priority values for the configured grant. A UE does notexpect to be provided PUCCH resources or PUSCH resources to reportHARQ-ACK information that start earlier than (N + 1) · (2048 + 144) · κ· 2^(µ) · T_(c) after the end of a last symbol of a last PSFCH receptionoccasion, from a number of PSFCH reception occasions that the UEgenerates HARQ-ACK information to report in a PUCCH or PUSCHtransmission, where – κ and T_(c) are defined in [4, TS 38.211] – µ =min (µ_(SL), µ_(UL)), where µ_(SL) is the SCS configuration of the SLBWP and µ_(UL) is the SCS configuration of the active UL BWP on theprimary cell – N is determined from µ according to Table 16.5-1

Table 16.5-1: Values of N With reference to slots for PUCCHtransmissions and for a number of PSFCH reception occasions ending inslot n, the UE provides the generated HARQ-ACK information in a PUCCHtransmission within slot n + k, subject to the overlapping conditions inClause 9.2.5, where k is a number of slots indicated by aPSFCH-to-HARQ_feedback timing indicator field, if present, in a DCIformat indicating a slot for PUCCH transmission to report the HARQ-ACKinformation, or k is provided by sl-PSFCH-ToPUCCH-CG-Type1-r16, k = 0corresponds to a last slot for a PUCCH |transmission that would overlapwith the last PSFCH reception occasion assuming that the start of thesidelink frame is same as the start of the downlink frame [4, TS36.211]. For a PSSCH transmission by a UE that is scheduled by a DCIformat, or for a SL configured grant Type 2 PSSCII transmissionactivated by a DCI format, the DCI format indicates to the UE that aPUCCH resource is not provided when a value of the PUCCH resourceindicator field is zero and a value of PSFCII-to-HARQ feedback timingindicator field, if present, is zero. For a SL configured grant Type 1PSSCH transmission, a PUCCH resource can be provided bysl-NIPUCCH-AN-r16 and sl-PSFCH-ToPUCCH-CG-Type1-r16. If a PUCCH resourceis not provided, the UE does not transmit a PUCCH with generatedHARQ-ACK information from PSFCH reception occasions. For a PUCCHtransmission with HARQ-ACK informmtion, a UE determines a PUCCH resourceafter determining a set of PUCCH resources for O_(UCI) HARQ-ACKinformation bits, as described in Clause 9.2.1. The PUCCH on a PUCCHresource indicator field [5, TS 38.212] in a last DC1 format 3_0, amongthe DCI formats 3_0 that have a value of a PSFCH-to-HARQ_feedback timingindicator field indicating a same slot for the PUCCH transmission, thatthe UE detects and for which the UE transmits corresponding HARQ-ACKinformation in the PUCCH where, for PUCCH resource determination,detected DCI formats are indexed in an ascending order across PDCCHmonitoring occasion indexes. A UE does not expect to multiplex HARQ-ACKinformation for more than one SL configured grants in a same PUCCH. Apriority value of a PUCCH transmission with one or more sidelinkHARQ-ACK information bits is the smallest priority value for the one ormore HARQ-ACK information bits. In the following, the CRC for DCI format3_0 is scrambled with a SL-RNTI or a SL-CS-RNTI.

FIGS. 10A to 10C illustrate three cast types applicable to the presentdisclosure. The embodiment of FIGS. 10A to 10C may be combined withvarious embodiments of the present disclosure. Specifically, FIG. 10Aexemplifies broadcast-type SL communication, FIG. 10B exemplifiesunicast type-SL communication, and FIG. 10C exemplifies groupcast-typeSL communication. In case of the unicast-type SL communication, a UE mayperform one-to-one communication with respect to another UE. In case ofthe groupcast-type SL transmission, the UE may perform SL communicationwith respect to one or more UEs in a group to which the UE belongs. Invarious embodiments of the present disclosure, SL groupcastcommunication may be replaced with SL multicast communication, SLone-to-many communication, or the like.

Hybrid Automatic Request (HARQ) Procedure

SL HARQ feedback may be enabled for unicast. In this case, in anon-codeblock group (non-CBG) operation, when the receiving UE decodes a PSCCHdirected to it and succeeds in decoding an RB related to the PSCCH, thereceiving UE may generate an HARQ-ACK and transmit the HARQ-ACK to thetransmitting UE. On the other hand, after the receiving UE decodes thePSCCH directed to it and fails in decoding the TB related to the PSCCH,the receiving UE may generate an HARQ-NACK and transmit the HARQ-NACK tothe transmitting UE.

For example, SL HARQ feedback may be enabled for groupcast. For example,in a non-CBG operation, two HARQ feedback options may be supported forgroupcast.

(1) Groupcast option 1: When the receiving UE decodes a PSCCH directedto it and then fails to decode a TB related to the PSCCH, the receivingUE transmits an HARQ-NACK on a PSFCH to the transmitting UE. On thecontrary, when the receiving UE decodes the PSCCH directed to it andthen succeeds in decoding the TB related to the PSCCH, the receiving UEmay not transmit an HARQ-ACK to the transmitting UE.

(2) Groupcast option 2: When the receiving UE decodes a PSCCH directedto it and then fails to decode a TB related to the PSCCH, the receivingUE transmits an HARQ-NACK on a PSFCH to the transmitting UE. On thecontrary, when the receiving UE decodes the PSCCH directed to it andthen succeeds in decoding the TB related to the PSCCH, the receiving UEmay transmit an HARQ-ACK to the transmitting UE on the PSFCH.

For example, when groupcast option 1 is used for SL HARQ feedback, allUEs performing groupcast communication may share PSFCH resources. Forexample, UEs belonging to the same group may transmit HARQ feedbacks inthe same PSFCH resources.

For example, when groupcast option 2 is used for SL HARQ feedback, eachUE performing groupcast communication may use different PSFCH resourcesfor HARQ feedback transmission. For example, UEs belonging to the samegroup may transmit HARQ feedbacks in different PSFCH resources.

In the present disclosure, HARQ-ACK may be referred to as ACK, ACKinformation, or positive-ACK information, and HARQ-NACK may be referredto as NACK, NACK information, or negative-ACK information.

SL Measurement and Reporting

For the purpose of QoS prediction, initial transmission parametersetting, link adaptation, link management, admission control, and so on,SL measurement and reporting (e.g., an RSRP or an RSRQ) between UEs maybe considered in SL. For example, the receiving UE may receive an RSfrom the transmitting UE and measure the channel state of thetransmitting UE based on the RS. Further, the receiving UE may reportCSI to the transmitting UE. SL-related measurement and reporting mayinclude measurement and reporting of a CBR and reporting of locationinformation. Examples of CSI for V2X include a channel quality indicator(CQI), a precoding matrix index (PMI), a rank indicator (RI), an RSRP,an RSRQ, a path gain/pathloss, an SRS resource indicator (SRI), a CSI-RSresource indicator (CRI), an interference condition, a vehicle motion,and the like. CSI reporting may be activated and deactivated dependingon a configuration.

For example, the transmitting UE may transmit a channel stateinformation-reference signal (CSI-RS) to the receiving UE, and thereceiving UE may measure a CQI or RI using the CSI-RS. For example, theCSI-RS may be referred to as an SL CSI-RS. For example, the CSI-RS maybe confined to PSSCH transmission. For example, the transmitting UE maytransmit the CSI-RS in PSSCH resources to the receiving UE.

Sidelink Congestion Control

For example, the UE may determine whether an energy measured in a unittime/frequency resource is equal to or greater than a predeterminedlevel and control the amount and frequency of its transmission resourcesaccording to the ratio of unit time/frequency resources in which theenergy equal to or greater than the predetermined level is observed. Inthe present disclosure, a ratio of time/frequency resources in which anenergy equal to or greater than a predetermined level is observed may bedefined as a CBR. The UE may measure a CBR for a channel/frequency. Inaddition, the UE may transmit the measured CBR to the network/BS.

FIG. 11 illustrates resource units for CBR measurement applicable to thepresent disclosure. The embodiment of FIG. 11 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 11 , a CBR may refer to the number of subchannels ofwhich the RS SI measurements are equal to or larger than a predeterminedthreshold as a result of measuring an RSSI in each subchannel during aspecific period (e.g., 100 ms) by a UE. Alternatively, a CBR may referto a ratio of subchannels having values equal to or greater than apredetermined threshold among subchannels during a specific period. Forexample, in the embodiment of FIG. 11 , on the assumption that thehatched subchannels have values greater than or equal to a predeterminedthreshold, the CBR may refer to a ratio of hatched subchannels for atime period of 100 ms. In addition, the UE may report the CBR to the BS.

For example, when a PSCCH and a PSSCH are multiplexed in a frequencydomain, the UE may perform one CBR measurement in one resource pool.When PSFCH resources are configured or preconfigured, the PSFCHresources may be excluded from the CBR measurement.

Further, congestion control considering a priority of traffic (e.g.packet) may be necessary. To this end, for example, the UE may measure achannel occupancy ratio (CR). Specifically, the UE may measure the CBR,and the UE may determine a maximum value CRlimitk of a channel occupancyratio k (CRk) that can be occupied by traffic corresponding to eachpriority (e.g., k) based on the CBR. For example, the UE may derive themaximum value CRlimitk of the channel occupancy ratio with respect to apriority of each traffic, based on a predetermined table of CBRmeasurement values. For example, in case of traffic having a relativelyhigh priority, the UE may derive a maximum value of a relatively greatchannel occupancy ratio. Thereafter, the UE may perform congestioncontrol by restricting a total sum of channel occupancy ratios oftraffic, of which a priority k is lower than i, to a value less than orequal to a specific value. Based on this method, the channel occupancyratio may be more strictly restricted for traffic having a relativelylow priority.

In addition thereto, the UE may perform SL congestion control by using amethod of adjusting a level of transmit power, dropping a packet,determining whether retransmission is to be performed, adjusting atransmission RB size (MCS coordination), or the like.

An example of SL CBR and SL RSSI is as follows. In the descriptionbelow, the slot index may be based on a physical slot index.

A SL CBR measured in slot n is defined as the portion of sub-channels inthe resource pool whose SL RSSI measured by the UE exceed a(pre-)configured threshold sensed over a CBR measurement window [n-a,n-1]. Herein, a is equal to 100 or 100·2^(µ) slots, according to higherlayer parameter sl-TimeWindowSizeCBR. The SL CBR is applicable forRRC_IDLE intra-frequency, RRC_IDLE inter-frequency, RRC_CONNECTEDintra-frequency, or RRC_CONNECTED inter-frequency

A SL RSSI is defined as the linear average of the total received power(in [W]) observed in the configured sub-channel in OFDM symbols of aslot configured for PSCCH and PSSCH, starting from the 2^(nd) OFDMsymbol. For frequency range 1, the reference point for the SL RSSI shallbe the antenna connector of the UE. For frequency range 2, SL RSSI shallbe measured based on the combined signal from antenna elementscorresponding to a given receiver branch. For frequency range 1 and 2,if receiver diversity is in use by the UE, the reported SL RSSI valueshall not be lower than the corresponding SL RSSI of any of theindividual receiver branches. The SL RSSI is applicable for RRC_IDLEintra-frequency, RRC_IDLE inter-frequency, RRC_CONNECTED intra-frequencyor RRC_CONNECTED inter-frequency.

An example of an SL (Channel occupancy Ratio) is as follows.. The SL CRevaluated at slot n is defined as the total number of sub-channels usedfor its transmissions in slots [n-a, n-1] and granted in slots [n, n+b]divided by the total number of configured sub-channels in thetransmission pool over [n-a, n+b]. The SL CR is applicable for RRC_IDLEintra-frequency, RRC_IDLE inter-frequency, RRC_CONNECTED intra-frequencyor RRC_CONNECTED inter-frequency. Herein, a may be a positive integerand b may be 0 or a positive integer. a and b may be determined by UEimplementation with a+b+1 = 1000 or 1000·2^(µ) slots, according tohigher layer parameter sl-TimeWindowSizeCR, b < (a+b+1)/2, and n+b shallnot exceed the last transmission opportunity of the grant for thecurrent transmission. The SL CR is evaluated for each (re)transmission.In evaluating SL CR, the UE shall assume the transmission parameter usedat slot n is reused according to the existing grant(s) in slot [n+1,n+b] without packet dropping. The slot index is based on physical slotindex. The SL CR can be computed per priority level. A resource isconsidered granted if it is a member of a selected sidelink grant asdefined in TS 38.321.

Positioning

FIG. 12 illustrates an example of an architecture of a 5G system capableof positioning a UE connected to an NG-RAN or an E-UTRAN, in accordancewith an embodiment of the present disclosure.

Referring to FIG. 12 , an AMF may receive a request for a locationservice related to a specific target UE from another entity such as agateway mobile location center (GMLC) or may autonomously determine toinitiate the location service on behalf of the specific target UE. TheAMF may then transmit a location service request to a locationmanagement function (LMF). Upon receipt of the location service request,the LMF may process the location service request and return a processingresult including information about an estimated location of the UE tothe AMF. On the other hand, when the location service request isreceived from another entity such as the GMLC, the AMF may deliver theprocessing result received from the LMF to the other entity.

A new generation evolved-NB (ng-eNB) and a gNB, which are networkelements of an NG-RAN capable of providing measurement results forpositioning, may measure radio signals for the target UE and transmitresult values to the LMF. The ng-eNB may also control some transmissionpoints (TPs) such as remote radio heads or positioning reference signal(PRS)-dedicated TPs supporting a PRS-based beacon system for an E-UTRA.

The LMF is connected to an enhanced serving mobile location center(E-SMLC), and the E-SMLC may enable the LMF to access an E-UTRAN. Forexample, the E-SMLC may enable the LMF to support observed timedifference of arrival (OTDOA), which is one of positioning methods inthe E-UTRAN, by using DL measurements obtained by the target UE throughsignals transmitted by the eNB and/or the PRS-dedicated TPs in theE-UTRAN.

The LMF may be connected to an SUPL location platform (SLP). The LMF maysupport and manage different location determination services for targetUEs. The LMF may interact with the serving ng-eNB or serving gNB of atarget UE to obtain a location measurement of the UE. For positioningthe target UE, the LMF may determine a positioning method based on alocation service (LCS) client type, a QoS requirement, UE positioningcapabilities, gNB positioning capabilities, and ng-eNB positioningcapabilities, and apply the positioning method to the serving gNB and/orthe serving ng-eNB. The LMF may determine additional information such asa location estimate for the target UE and the accuracy of the positionestimation and a speed. The SLP is a secure user plane location (SUPL)entity responsible for positioning through the user plane.

The UE may measure a DL signal through sources such as the NG-RAN andE-UTRAN, different global navigation satellite systems (GNSSes), aterrestrial beacon system (TBS), a wireless local area network (WLAN)access point, a Bluetooth beacon, and a UE barometric pressure sensor.The UE may include an LCS application and access the LCS applicationthrough communication with a network to which the UE is connected orthrough another application included in the UE. The LCS application mayinclude a measurement and calculation function required to determine thelocation of the UE. For example, the UE may include an independentpositioning function such as a global positioning system (GPS) andreport the location of the UE independently of an NG-RAN transmission.The independently obtained positioning information may be utilized asauxiliary information of positioning information obtained from thenetwork.

FIG. 13 illustrates exemplary implementation of a network forpositioning a UE, in accordance with an embodiment of the presentdisclosure.

Upon receipt of a location service request when the UE is in aconnection management-IDLE (CM-IDLE) state, the AMF may establish asignaling connection with the UE and request a network trigger serviceto assign a specific serving gNB or ng-eNB. This operation is not shownin FIG. 13 . That is, FIG. 13 may be based on the assumption that the UEis in connected mode. However, the signaling connection may be releasedby the NG-RAN due to signaling and data deactivation during positioning.

Referring to FIG. 13 , a network operation for positioning a UE will bedescribed in detail. In step 1 a, a 5GC entity such as a GMLC mayrequest a location service for positioning a target UE to a serving AMF.However, even though the GMLC does not request the location service, theserving AMF may determine that the location service for positioning thetarget UE is required in step 1 b. For example, for positioning the UEfor an emergency call, the serving AMF may determine to perform thelocation service directly.

The AMF may then transmit a location service request to an LMF in step2, and the LMF may start location procedures with the serving-eNB andthe serving gNB to obtain positioning data or positioning assistancedata in step 3 a. Additionally, the LMF may initiate a locationprocedure for DL positioning with the UE in step 3 b. For example, theLMF may transmit positioning assistance data (assistance data defined in3GPP TS 36.355) to the UE, or obtain a location estimate or locationmeasurement. Although step 3 b may be additionally performed after step3 a, step 3 b may be performed instead of step 3 a.

In step 4, the LMF may provide a location service response to the AMF.The location service response may include information indicating whetherlocation estimation of the UE was successful and the location estimateof the UE. Then, when the procedure of FIG. 13 is initiated in step 1 a,the AMF may deliver the location service response to the 5GC entity suchas the GMLC. When the procedure of FIG. 13 is initiated in step 1 b, theAMF may use the location service response to provide the locationservice related to an emergency call or the like.

FIG. 14 illustrates exemplary protocol layers used to support LTEpositioning protocol (LPP) message transmission between an LMF and a UE,in accordance with an embodiment of the present disclosure.

An LPP PDU may be transmitted in a NAS PDU between the AMF and the UE.Referring to FIG. 14 , the LPP may be terminated between a target device(e.g., a UE in the control plane or a SUPL enabled terminal (SET) in theuser plane) and a location server (e.g., an LMF in the control plane oran SLP in the user plane). An LPP message may be transmitted in atransparent PDU over an intermediate network interface by using anappropriate protocol such as the NG application protocol (NGAP) via anNG-control plane (NG-C) interface or a NAS/RRC via LTE-Uu and NR-Uuinterfaces. The LPP allows positioning for NR and LTE in variouspositioning methods.

For example, the target device and the location server may exchangecapability information with each other, positioning assistance dataand/or location information over the LPP. Further, error information maybe exchanged and/or discontinuation of an LPP procedure may beindicated, by an LPP message.

FIG. 15 illustrates exemplary protocol layers used to support NRpositioning protocol A (NRPPa) PDU transmission between an LMF and anNG-RAN node, in accordance with an embodiment of the present disclosure.

NRPPa may be used for information exchange between the NG-RAN node andthe LMF. Specifically, NRPPa enables exchange of an enhanced-cell ID(E-CID) for a measurement transmitted from the ng-eNB to the LMF, datato support OTDOA positioning, and a Cell-ID and Cell location ID for NRCell ID positioning. Even without information about a related NRPPatransaction, the AMF may route NRPPa PDUs based on the routing ID of therelated LMF via an NG-C interface.

Procedures of the NRPPa protocol for positioning and data collection maybe divided into two types. One of the two types is a UE-associatedprocedure for delivering information (e.g., positioning information)about a specific UE, and the other type is a non-UE-associated procedurefor delivering information (e.g., gNB/ng-eNB/TP timing information)applicable to an NG-RAN node and related TPs. The two types ofprocedures may be supported independently or simultaneously.

Positioning methods supported by the NG-RAN include GNSS, OTDOA, E-CID,barometric pressure sensor positioning, WLAN positioning, Bluetoothpositioning, terrestrial beacon system (TBS), and UL time difference ofarrival (UTDOA). Although a UE may be positioned in any of the abovepositioning methods, two or more positioning methods may be used toposition the UE.

Observed Time Difference of Arrival (OTDOA)

FIG. 16 is a diagram illustrating an OTDOA positioning method, inaccordance with an embodiment of the present disclosure.

In the OTDOA positioning method, a UE utilizes measurement timings of DLsignals received from multiple TPs including an eNB, ng-eNB, and aPRS-dedicated TP. The UE measures the timings of the received DL signalsusing positioning assistance data received from a location server. Thelocation of the UE may be determined based on the measurement resultsand the geographical coordinates of neighboring TPs.

A UE connected to a gNB may request a measurement gap for OTDOAmeasurement from a TP. When the UE fails to identify a single frequencynetwork (SFN) for at least one TP in OTDOA assistance data, the UE mayuse an autonomous gap to acquire the SFN of an OTDOA reference cellbefore requesting a measurement gap in which a reference signal timedifference (RSTD) is measured.

Herein, an RSTD may be defined based on a smallest relative timedifference between the boundaries of two subframes received from areference cell and a measurement cell. That is, the RSTD may becalculated as a relative timing difference for between a time when theUE receives the start of a subframe from the reference cell and a timewhen the UE receives the start of a subframe from the measurement cellwhich is closest to the subframe received from the reference cell. Thereference cell may be selected by the UE.

For accurate OTDOA measurement, it is necessary to measure the time ofarrivals (TOAs) of signals received from three or more geographicallydistributed TPs or BSs. For example, TOAs for TP 1, TP 2, and TP 3 maybe measured, an RSTD for TP 1-TP 2, an RSTD for TP 2-TP 3, and an RSTDfor TP 3-TP 1 may be calculated based on the three TOAs, geometrichyperbolas may be determined based on the calculated RSTDs, and a pointwhere these hyperbolas intersect may be estimated as the location of theUE. Accuracy and/or uncertainty may be involved in each TOA measurement,and thus the estimated UE location may be known as a specific rangeaccording to the measurement uncertainty.

For example, an RSTD for two TPs may be calculated by Equation 1.

$\begin{array}{l}{RST..Dt.1 =} \\{\frac{\sqrt{\left( {x_{1}\text{-}x_{1}} \right)^{2} + \left( {y_{1}\text{-}y_{1}} \right)^{2}}}{c}\text{-}\frac{\sqrt{\left( {x_{1}\text{-}x_{1}} \right)^{2} + \left( {y_{1}\text{-}y_{1}} \right)}}{c} + \left( {T_{1}\text{-}T_{1}} \right) + \left( {n_{1}\text{-}n_{1}} \right)}\end{array}$

where c is the speed of light, {xt, yt} is the (unknown) coordinates ofthe target UE, {xi, yi} is the coordinates of a (known) TP, and {x1, y1}is the coordinates of a reference TP (or another TP). (Ti-T1) is atransmission time offset between the two TPs, which may be referred toas “real time difference” (RTD), and ni and n1 may represent valuesrelated to UE TOA measurement errors.

E-CID (Enhanced Cell ID)

In cell ID (CID) positioning, the location of a UE may be measured basedon geographic information about the serving ng-eNB, serving gNB and/orserving cell of the UE. For example, the geographic information aboutthe serving ng-eNB, the serving gNB, and/or the serving cell may beobtained by paging, registration, or the like.

For E-CID positioning, an additional UE measurement and/or NG-RAN radioresources may be used to improve a UE location estimate in addition tothe CID positioning method. In the E-CID positioning method, althoughsome of the same measurement methods as in the measurement controlsystem of the RRC protocol may be used, an additional measurement isgenerally not performed only for positioning the UE. In other words, aseparate measurement configuration or measurement control message maynot be provided to position the UE, and the UE may also report ameasured value obtained by generally available measurement methods,without expecting that an additional measurement operation only forpositioning will be requested.

For example, the serving gNB may implement the E-CID positioning methodusing an E-UTRA measurement received from the UE.

Exemplary measurement elements that are available for E-CID positioningare given as follows.

UE measurements: E-UTRA RSRP, E-UTRA RSRQ, UE E-UTRA Rx-Tx timedifference, GSM EDGE random access network (GERAN)/WLAN RSSI, UTRANcommon pilot channel (CPICH) received signal code power (RSCP), andUTRAN CPICH EOM.

E-UTRAN measurements: ng-eNB Rx-Tx time difference, timing advance(TADV), and angle of arrival (AoA).

TADVs may be classified into Type 1 and Type 2 as follows.

TADV Type 1=(ng-eNB Rx-Tx time difference)+(UE E-UTRA Rx-Tx timedifference)

TADV Type 2=ng-eNB Rx-Tx time difference

On the other hand, an AoA may be used to measure the direction of theUE. The AoA may be defined as an estimated angle of the UE with respectto the location of the UE counterclockwise from a BS/TP. A geographicalreference direction may be North. The BS/TP may use a UL signal such asa sounding reference signal (SRS) and/or a DMRS for AoA measurement. Asthe arrangement of antenna arrays is larger, the measurement accuracy ofthe AoA is higher. When the antenna arrays are arranged at the sameinterval, signals received at adjacent antenna elements may have aconstant phase change (phase rotation).

UTDOA (UL Time Difference of Arrival)

A UTDOA is a method of determining the location of a UE by estimatingthe arrival time of an SRS. When the estimated SRS arrival time iscalculated, a serving cell may be used as a reference cell to estimatethe location of the UE based on the difference in arrival time fromanother cell (or BS/TP). In order to implement the UTDOA method, anE-SMLC may indicate the serving cell of a target UE to indicate SRStransmission to the target UE. Further, the E-SMLC may provide aconfiguration such as whether an SRS is periodic/aperiodic, a bandwidth,and frequency/group/ sequence hopping.

Specific Embodiments of the Present Disclosure

Hereinafter, the present disclosure describes a technique for performingpositioning using a beamformed signal in a wireless communicationsystem. Specifically, the present disclosure proposes a techniquecapable of reducing a time required for positioning by integrating apositioning procedure and a beam management procedure into oneprocedure.

In vehicle-related applications such as autonomous driving,high-precision positioning is an essential technology element. To thisend, transmission of a wideband positioning reference signal (PRS) isrequired. Due to the lack of spectrum of the existing licensed band, itis necessary to use a mmWave unlicensed band, and, in this case,scheduling and beam management for PRS transmission in a communicationlink between mm Wave vehicles, that is, in a mmWave V2X sidelink, isessentially required. Accordingly, the present disclosure describesvarious embodiments capable of efficiently performing PRS scheduling andbeam management.

FIG. 17 illustrates the concept of a positioning procedure based on apositioning reference signal (PRS) request in a wireless communicationsystem according to an embodiment of the present disclosure.

Referring to FIG. 17 , a first vehicle terminal 1710 tries to performpositioning. A second vehicle terminal 1720 and two fixed nodes 1730 aand 1730 b are present around the first vehicle terminal 1710. Here,each of the fixed nodes 1730 a and 1730 b may be a road side unit (RSU)or a base station. The fixed nodes 1730 a and 1730 b may transmit PRSsfor positioning of a neighboring device (e.g., the first vehicleterminal 1710). That is, the fixed nodes 1730 a and 1730 b mayperiodically transmit the PRSs without a separate request. Each of thefixed nodes 1730 a and 1730 b may repeatedly transmit PRSs according toa set pattern. Accordingly, the first vehicle terminal 1710 may measurethe reception times of the received PRSs and perform direct positioningbased on the reception times or transmit the measurement result to anupper node (e.g., an LMF).

In general, in order to perform positioning according to the TDOA orOTDOA technique, more than a certain number of signal sources arerequired. If there are enough fixed nodes (hereinafter, “fixed PRSsources”) that transmit PRSs in the vicinity of the first vehicleterminal 1710 to perform positioning, the first vehicle terminal 1710may perform positioning using the PRS signals from the neighboring fixedPRS sources. However, when a sufficient number of fixed PRS sources isnot present in the vicinity, it may be difficult to perform apositioning operation.

In this case, according to various embodiments, the first vehicleterminal 1710 may request transmission of the PRS from another terminal1720, for example, the second vehicle terminal 1720. Accordingly, thefirst vehicle terminal 1710 may further secure a device that provides aPRS (hereinafter, “PRS source”) and may perform positioning.Furthermore, even if there are no fixed PRS sources in the vicinity,according to various embodiments, the first vehicle terminal 1710 mayutilize a plurality of other terminals including the second vehicleterminal 1720 as PRS sources to perform positioning.

According to the procedure described with reference to FIG. 17 , theterminal may request that another terminal should operate as a PRSsource, and the other terminal may operate as a PRS source. In thiscase, the terminals may perform mutual communication using a beamformedsignal. In this case, a procedure for matching a transmit beam and areceive beam between terminals needs to be preceded. If theaforementioned procedure and the beam matching procedure are separatelyperformed, time latency until final PRS transmission will increase.

In other words, in order to transmit/receive a PRS in a millimeter wavesidelink system, a procedure for requesting PRS transmission andallocating resources and a procedure for managing a beam are required.When the two procedures are sequentially performed, excessive timelatency may occur in a vehicle-to-vehicle communication environment withstrict end-to-end latency conditions. Therefore, it is necessary tominimize the time latency until the final PRS transmission byorganically combining the PRS scheduling procedure and the beammanagement procedure.

Accordingly, the present disclosure proposes a method of organicallycombining the above-described procedure for requesting PRS transmissionand allocating resources and a procedure for matching beams between twovehicle terminals in order to exchange PRSs in a millimeter wavesidelink system. For beam matching, beamforming may be applied tomessages or signals transmitted by the aforementioned vehicle terminals,and beam-related reports may be included in some messages.

FIG. 18 illustrates an example of a method of operating a terminal forperforming positioning in a wireless communication system according toan embodiment of the present disclosure. FIG. 18 illustrates a method ofoperating a terminal (e.g., the first vehicle terminal 1710) forreceiving a RPS signal.

Referring to FIG. 18 , in step S1801, the terminal transmits a PRSrequest message. In other words, the terminal transmits a messagerequesting that a neighboring terminal should operate as a PRS source.The PRS request message includes information indicating that PRStransmission is requested. The PRS request message may be transmittedwithout specifying a destination terminal. In this case, according to anembodiment, the terminal repeatedly transmits the PRS request messageusing a plurality of beams. That is, the terminal transmits the PRSrequest messages using different beams.

In step S1803, the terminal receives a PRS response message. Theterminal receives a PRS response message from another terminal that hasreceived the PRS request message. The PRS response message includesidentification information of another terminal as a response indicatingthat the other terminal will transmit the PRS. Also, according to anembodiment, the PRS response message may include information related toselection of at least one beam (e.g., an indication of the selectedbeam, measurement information, etc.). In this case, information relatedto selection may be expressed explicitly or implicitly. Although theinformation related to selection indicates a transmit beam, a receivebeam for receiving a signal transmitted from the other terminal may alsobe confirmed according to channel reciprocity.

In step S1805, the terminal transmits a PRS scheduling message. Thescheduling message includes information related to a resource fortransmitting the PRS. The PRS scheduling message may be transmittedtogether with a reference signal, for decoding in another terminal. Inthis case, according to an embodiment, the terminal transmits the PRSscheduling message through at least one beam selected by anotherterminal. Furthermore, in order to determine the receive beam of anotherterminal, the terminal may repeatedly transmit a PRS scheduling message.Through this, before the PRS transmission is performed, a beam pair forPRS transmission of another terminal and PRS reception of the terminalis determined.

In step S1807, the terminal receives the PRS. The terminal may receivethe PRS transmitted from another terminal in the resource indicated bythe PRS scheduling message. If necessary, the PRS may be receivedtogether with positioning assist data. For example, the positioningassist information may include location information (e.g., coordinates,distance, etc.) of another terminal. In this case, according to anembodiment, the terminal receives the PRS using the receive beamconfirmed by the information related to selection included in the PRSresponse message.

Although not shown in FIG. 18 , the terminal may perform positioningusing the PRS received from another terminal and the PRSs received fromat least one other PRS source (e.g., another terminal, RSU, basestation, etc.). Specifically, the terminal may calculate a timedifference between PRSs received from different PRS sources. Thecalculated time difference information may be transmitted to an uppernode or may be used directly by the terminal for location calculation.

FIG. 19 illustrates an example of a method of operating a terminalassisting positioning in a wireless communication system according to anembodiment of the present disclosure. FIG. 19 illustrates a method ofoperating a terminal (e.g., the second vehicle terminal 1720) fortransmitting a RPS signal.

Referring to FIG. 19 , in step S1901, the terminal receives a PRSrequest message. In other words, the terminal receives a messagerequesting to operate as a PRS source from another terminal. The PRSrequest message includes information indicating that PRS transmission isrequested. Since the terminal may not know the direction of anotherterminal or a beam direction suitable for communication with anotherterminal, according to an embodiment, the terminal may receive thesignal of the PRS request message using a wide beam. In this case, sinceanother terminal repeatedly transmits the PRS request message throughdifferent transmit beams, the terminal may select at least one preferredtransmit beam based on whether the PRS request message is received and ameasurement result.

In step S1903, the terminal transmits a PRS response message. Theterminal transmits a PRS response message to another terminal that hastransmitted the PRS request message. The PRS response message includesidentification information of the terminal as a response indicating thatthe terminal will transmit the PRS. Also, according to an embodiment,the PRS response message may include information related to selection ofat least one beam (e.g., an indication of the selected beam, measurementinformation, etc.). In this case, information related to selection maybe expressed explicitly or implicitly.

In step S1905, the terminal receives a PRS scheduling message. Thescheduling message includes information related to a resource fortransmitting the PRS. The PRS scheduling message may be receivedtogether with a reference signal to enable channel estimation fordecoding. At this time, according to an embodiment, another terminalrepeatedly transmits a PRS scheduling message. Accordingly, the terminalmay attempt to receive the PRS scheduling message using a plurality ofreceive beams, and may select at least one preferred receive beam basedon whether the PRS scheduling message is received and a measurementresult. Through this, before PRS transmission is performed,determination of a beam pair for PRS transmission of the terminal andPRS reception of another terminal is completed.

In step S1907, the terminal transmits the PRS. The terminal may transmitthe PRS received from another terminal in the resource indicated by thePRS scheduling message. If necessary, the terminal may transmit the PRSand positioning assist data together. For example, the positioningassist information may include location information (e.g., coordinates,distance, etc.) of the terminal. In this case, according to anembodiment, the terminal transmits the PRS using a transmit beamcorresponding to a receive beam selected based on the PRS schedulingmessage.

As in the embodiments described with reference to FIGS. 18 and 19 , PRSsource securing and beam matching may be performed through oneprocedure. Through this, PRS transmission and reception using abeamformed signal between the first terminal requesting PRS transmissionand the second terminal transmitting the PRS may be performed quickly.Specifically, the second terminal selects the transmit beam of the firstterminal based on the PRS request message and feeds back the selectedbeam through the PRS response message, so that the first terminal maydetermine the beam to be used for PRS reception. In addition, since thefirst terminal repeatedly transmits the PRS scheduling message using thesame beam, the second terminal may obtain information related to aresource for PRS transmission, measure a receive beam, and determine abeam to be used for PRS transmission.

In the above procedure, the transmitted messages may include informationindicating the purpose or type of each message, and information onresources for transmitting subsequent messages. For example, the PRSrequest message includes information indicating that PRS transmission isrequested and information on resources (e.g., resource pool) fortransmitting a PRS response message, and the included information isexpressed explicitly or implicitly.

Similarly, information on selection of the beam included in the PRSresponse message may be expressed explicitly or implicitly. For example,a beam index may be included in the PRS response message. As anotherexample, by allocating unique response resources to each beam, an effectof implicitly performing beam reporting when transmitting a PRS responsemessage may be obtained. In addition, by allocating different requestedtransmission resources for each service, an effect of signaling aservice may be obtained.

Hereinafter, a PRS request procedure according to a more specificembodiment will be described with reference to FIG. 20 . In FIG. 20 , aterminal requesting a PRS is referred to as an “agent vehicle”, and aterminal transmitting the PRS is referred to as an “anchor vehicle”.

FIG. 20 illustrates an example of a procedure for transmitting a PRSbased on a request in a wireless communication system according to anembodiment of the present disclosure. FIG. 20 illustrates signalexchange between an agent vehicle 2010 and an anchor vehicle 2020. Inaddition, FIG. 20 illustrates transmit beamforming or receivebeamforming of each of the agent vehicle 2010 and the anchor vehicle 202during transmission and reception of each message.

Referring to FIG. 20 , in step S2001, the agent vehicle 2010 maytransmit a PRS request message, and the anchor vehicle 2020 may receivea PRS request message. The agent vehicle 2010 may request PRStransmission from a neighboring vehicle for positioning. Here, the PRSrequest message includes information indicating that PRS transmission isrequested. The request for PRS transmission may be expressed by anexplicit indicator (e.g., a service ID corresponding to the PRS request)or may be expressed implicitly. For example, the PRS request message maybe transmitted through a resource pool allocated for a positioningservice (hereinafter, “PRS request resource pool”) to report the PRStransmission request. When the PRS request resource pool is used, theanchor vehicle 3020 may receive a PRS request message by monitoring thePRS request resource pool.

According to an embodiment, the PRS request message may be in the formof a discovery signal, and the PRS request may be signaled through aservice ID in the discovery signal. Alternatively, different individualdiscovery resource pools may be allocated according to the requestedservice. For example, the discovery resource pool may be allocated asshown in FIG. 21 . Referring to FIG. 21 , a plurality of resource pools2102 to 2106 may be allocated to different time-frequency domains. Ifthe resource pool 2102 of the plurality of resource pools 2102 to 2106is allocated for a positioning service, the PRS request message istransmitted through the resource pool 2102.

In this case, the anchor vehicle 2020 interested in the positioningservice monitors only the discovery resource pool allocated for thepositioning service. The PRS request message may be in the form of abeamformed signal, and may be repeatedly transmitted using differentbeams. The PRS request message may include the ID of the agent vehicle2010 and information related to at least one resource for enablinganother vehicle receiving it to send a response. PRS requeststransmitted using different beams may include different PRS requestresponse resource information.

In step S2003, the anchor vehicle 2020 transmits a PRS request responsemessage. When transmitting the PRS after receiving the PRS requestmessage, the anchor vehicle 2020 may transmit a PRS request responsemessage. The PRS request response message may include IDs of the agentvehicle 2010 and the anchor vehicle 2020, and may include information onat least one resource for enabling the agent vehicle 2010 to transmitthe PRS scheduling message. At this time, the agent vehicle 2010 may notknow which receive beam may be used to receive the signal transmittedfrom the anchor vehicle 2020. Accordingly, the agent vehicle 2010attempts to receive the RPS request response message using a pluralityof receive beams, and receives the RPS request response message using atleast one of the plurality of receive beams.

When PRS request messages are received using multiple beams, the PRSrequest response message may include information related to beam(s)preferred by the anchor vehicle 2020. The information related to thepreferred beam(s) may include a beam index, a reference signal receivedpower (RSRP) of the beam, and the like. Alternatively, when the anchorvehicle 2020 selects a PRS request response resource specified by a PRSrequest message associated with a specific beam, the agent vehicle 2010receives a PRS request response message using the resource, therebyknowing the transmit beam information preferred by the anchor vehicle2020.

For example, resource pools may be allocated as shown in FIG. 22 .Referring to FIG. 22 , a plurality of resource pools 2202 to 2214corresponding to different beams may be allocated. When the anchorvehicle 2020 selects the PRS request message transmitted through beam-4,the anchor vehicle 2030 transmits a PRS request response message throughthe resource pool 2208 corresponding to beam-4. When the anchor vehicle2020 receives the PRS request, it is possible to measure the RSRP fromthe received signal and to determine whether to transmit the PRS requestresponse according to whether the measured RSRP value exceeds a specificthreshold. In this case, the threshold may be a value set by a networkor preset in the terminal.

In step S2005, the agent vehicle 2010, which has received the PRSrequest response message, may transmit a PRS scheduling message. The PRSscheduling message may include information related to at least oneresource for enabling the anchor vehicle 2020 to transmit the PRS. ThePRS scheduling information may be beamformed, and, for the PRSscheduling message, the beam may be a beam related to beam informationincluded in the PRS request response message or a beam related to aresource through which the PRS request response is received. The PRSscheduling message may be multiplexed together with a reference signal,and the reference signal may be used to decode the PRS schedulingmessage. In addition, the PRS scheduling message may be repeatedlytransmitted using the same beam together with the reference signal. Inthis case, the PRS scheduling message or the reference signal may beused to select an optimal receive beam in the anchor vehicle 2020. Thereceive beam selected using the reference signal may be used as atransmit beam for enabling the anchor vehicle 2020 to transmit the PRSaccording to the principle of channel reciprocity.

In step S2007, the anchor vehicle 2020 transmits a PRS. The anchorvehicle 2020, which has received the PRS scheduling message, may obtainresource information for transmitting the PRS. In addition, whenreceiving a plurality of PRS scheduling messages, the anchor vehicle2020 may receive PRS scheduling messages using different beams, and mayselect at least one receive beam through measurement such as RSRP. Theselected receive beam(s) may be a beam suitable for transmissionaccording to the principle of transmission/reception channelreciprocity, and may be used for PRS transmission. The PRS may berepeatedly transmitted, and, in this case, may be transmitted using thesame transmit beam or different transmit beams. The PRS may bemultiplexed with the positioning assist data, and the PRS may be used todecode the positioning assist data. The positioning assist data mayinclude coordinates of the anchor vehicle 2020 or information (e.g.,coordinates, distance, etc.) of a fixed reference that the anchorvehicle 2020 has.

In the embodiment described with reference to FIG. 20 , the agentvehicle 2010 may repeatedly transmit the PRS scheduling message todetermine the receive beam of the anchor vehicle 2020. In this case, thenumber of repeated transmissions is preferably equal to the number ofcandidate receive beams available in the anchor vehicle 2020. Accordingto another embodiment, if the anchor vehicle 2020 has the capability tosimultaneously form a plurality of receive beams, the PRS schedulingmessage may be transmitted only the number of times (e.g., once) lessthan the number of candidate receive beams available in the anchorvehicle 2020. To this end, the agent vehicle 2010 needs to obtaininformation related to the beamforming capability of the anchor vehicle2020. Therefore, according to another embodiment, before or during theprocedure of FIG. 20 or through one of the messages described in FIG. 20, the agent vehicle 2010 may obtain information on the beamformingcapability of the anchor vehicle 2020. For example, the information onthe beamforming capability may indicate the number of transmissions of asignal (e.g., a PRS scheduling message) necessary for the anchor vehicle2020 to determine a receive beam.

Also, in the procedure described with reference to FIG. 20 , accordingto an embodiment, the PRS request message and the PRS request responsemessage may be transmitted through the resource pool. In this case,information on the resource pool may be provided through a procedureseparate from the procedure illustrated in FIG. 20 . For example,information on the resource pool may be included in system informationtransmitted by the base station or may be predefined.

As described above, the present disclosure proposes a new procedure inwhich a PRS request procedure and a beam management procedure areorganically combined. Using the proposed procedure, the PRS requestprocedure and the beam management procedure may be performed inparallel, thereby reducing the time latency until the final PRStransmission.

System and Various Devices to Which Embodiments of the PresentDisclosure Are Applicable

Various embodiments of the present disclosure may be combined with eachother.

Hereinafter, a device to which various embodiments of the presentdisclosure may be applied will be described. Although not limitedthereto, various descriptions, functions, procedures, proposals,methods, and/or operation flowcharts disclosed in this document may beapplied to various fields requiring wireless communication/connection(e.g., 5G) between devices.

Hereinafter, it will be described in more detail with reference to thedrawings. In the following drawings/description, the same referencenumerals may represent the same or corresponding hardware blocks,software blocks, or functional blocks, unless otherwise indicated.

FIG. 23 illustrates a communication system, in accordance with anembodiment of the present disclosure. The embodiment of FIG. 23 may becombined with various embodiments of the present disclosure.

Referring to FIG. 23 , the communication system applicable to thepresent disclosure includes a wireless device, a base station and anetwork. The wireless device refers to a device for performingcommunication using radio access technology (e.g., 5G NR or LTE) and maybe referred to as a communication/wireless/5G device. Without beinglimited thereto, the wireless device may include at least one of a robot100 a, vehicles 100 b-1 and 100 b-2, an extended reality (XR) device 100c, a hand-held device 100 d, a home appliance 100 e, an Internet ofThing (IoT) device 100 f, and an artificial intelligence (AI)device/server 100 g. For example, the vehicles may include a vehiclehaving a wireless communication function, an autonomous vehicle, avehicle capable of performing vehicle-to-vehicle communication, etc. Thevehicles 100 b-1 and 100 b-2 may include an unmanned aerial vehicle(UAV) (e.g., a drone). The XR device 100 c includes an augmented reality(AR)/virtual reality (VR)/mixed reality (MR) device and may beimplemented in the form of a head-mounted device (HMD), a head-updisplay (HUD) provided in a vehicle, a television, a smartphone, acomputer, a wearable device, a home appliance, a digital signage, avehicle or a robot. The hand-held device 100 d may include a smartphone,a smart pad, a wearable device (e.g., a smart watch or smart glasses), acomputer (e.g., a laptop), etc. The home appliance 100 e may include aTV, a refrigerator, a washing machine, etc. The IoT device 100 f mayinclude a sensor, a smart meter, etc. For example, the base station 120a to 120 e network may be implemented by a wireless device, and aspecific wireless device 120 a may operate as a base station/networknode for another wireless device.

Here, wireless communication technology implemented in wireless devices100 a to 100 f of the present disclosure may include Narrowband Internetof Things for low-power communication in addition to LTE, NR, and 6G. Inthis case, for example, NB-IoT technology may be an example of Low PowerWide Area Network (LPWAN) technology and may be implemented as standardssuch as LTE Cat NB1, and/or LTE Cat NB2, and is not limited to the namedescribed above. Additionally or alternatively, the wirelesscommunication technology implemented in the wireless devices 100 a to100 f of the present disclosure may perform communication based on LTE-Mtechnology. In this case, as an example, the LTE-M technology may be anexample of the LPWAN and may be called by various names includingenhanced Machine Type Communication (eMTC), and the like. For example,the LTE-M technology may be implemented as at least any one of variousstandards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTEnon-Bandwidth Limited (non-BL), 5) LTE-MTC, 6) LTE Machine TypeCommunication, and/or 7) LTE M, and is not limited to the name describedabove. Additionally or alternatively, the wireless communicationtechnology implemented in the wireless devices 100 a to 100 f of thepresent disclosure may include at least one of Bluetooth, Low Power WideArea Network (LPWAN), and ZigBee considering the low-powercommunication, and is not limited to the name described above. As anexample, the ZigBee technology may generate personal area networks (PAN)related to small/low-power digital communication based on variousstandards including IEEE 802.15.4, and the like, and may be called byvarious names.

The wireless devices 100 a to 100 f may be connected to the networkthrough the base station 120. AI technology is applicable to thewireless devices 100 a to 100 f, and the wireless devices 100 a to 100 fmay be connected to the AI server 100 g through the network. The networkmay be configured using a 3G network, a 4G (e.g., LTE) network or a 5G(e.g., NR) network, etc. The wireless devices 100 a to 100 f maycommunicate with each other through the base stations 120 a to 120 e orperform direct communication (e.g., sidelink communication) withoutthrough the base stations 120 a to 120 e. For example, the vehicles 100b-1 and 100 b-2 may perform direct communication (e.g., vehicle tovehicle (V2V)/vehicle to everything (V2X) communication). In addition,the IoT device 100 f (e.g., a sensor) may perform direct communicationwith another IoT device (e.g., a sensor) or the other wireless devices100 a to 100 f.

Wireless communications/connections 150 a, 150 b and 150 c may beestablished between the wireless devices 100 a to 100 f/the basestations 120 a to 120 e and the base stations 120 a to 120 e/the basestations 120 a to 120 e. Here, wireless communication/connection may beestablished through various radio access technologies (e.g., 5G NR) suchas uplink/downlink communication 150 a, sidelink communication 150 b (orD2D communication) or communication 150 c between base stations (e.g.,relay, integrated access backhaul (IAB). The wireless device and thebase station/wireless device or the base station and the base stationmay transmit/receive radio signals to/from each other through wirelesscommunication/connection 150 a, 150 b and 150 c. For example, wirelesscommunication/connection 150 a, 150 b and 150 c may enable signaltransmission/reception through various physical channels. To this end,based on the various proposals of the present disclosure, at least someof various configuration information setting processes fortransmission/reception of radio signals, various signal processingprocedures (e.g., channel encoding/decoding, modulation/demodulation,resource mapping/demapping, etc.), resource allocation processes, etc.may be performed.

FIG. 24 illustrates wireless devices, in accordance with an embodimentof the present disclosure. The embodiment of FIG. 24 may be combinedwith various embodiments of the present disclosure.

Referring to FIG. 24 , a first wireless device 200 a and a secondwireless device 200 b may transmit and receive radio signals throughvarious radio access technologies (e.g., LTE or NR). Here, {the firstwireless device 200 a, the second wireless device 200 b} may correspondto {the wireless device 100 x, the base station 120} and/or {thewireless device 100 x, the wireless device 100 x} of FIG. 23 .

The first wireless device 200 a may include one or more processors 202 aand one or more memories 204 a and may further include one or moretransceivers 206 a and/or one or more antennas 208 a. The processor 202a may be configured to control the memory 204 a and/or the transceiver206 a and to implement descriptions, functions, procedures, proposals,methods and/or operational flowcharts disclosed herein. For example, theprocessor 202 a may process information in the memory 204 a to generatefirst information/signal and then transmit a radio signal including thefirst information/signal through the transceiver 206 a. In addition, theprocessor 202 a may receive a radio signal including secondinformation/signal through the transceiver 206 a and then storeinformation obtained from signal processing of the secondinformation/signal in the memory 204 a. The memory 204 a may be coupledwith the processor 202 a, and store a variety of information related tooperation of the processor 202 a. For example, the memory 204 a maystore software code including instructions for performing all or some ofthe processes controlled by the processor 202 a or performing thedescriptions, functions, procedures, proposals, methods and/oroperational flowcharts disclosed herein. Here, the processor 202 a andthe memory 204 a may be part of a communication modem/circuit/chipdesigned to implement wireless communication technology (e.g., LTE orNR). The transceiver 206 a may be coupled with the processor 202 a totransmit and/or receive radio signals through one or more antennas 208a. The transceiver 206 a may include a transmitter and/or a receiver.The transceiver 206 a may be used interchangeably with a radio frequency(RF) unit. In the present disclosure, the wireless device may refer to acommunication modem/circuit/chip.

The second wireless device 200 b may perform wireless communicationswith the first wireless device 200 a and may include one or moreprocessors 202 b and one or more memories 204 b and may further includeone or more transceivers 206 b and/or one or more antennas 208 b. Thefunctions of the one or more processors 202 b, one or more memories 204b, one or more transceivers 206 b, and/or one or more antennas 208 b aresimilar to those of one or more processors 202 a, one or more memories204 a, one or more transceivers 206 a and/or one or more antennas 208 aof the first wireless device 200 a.

Hereinafter, hardware elements of the wireless devices 200 a and 200 bwill be described in greater detail. Without being limited thereto, oneor more protocol layers may be implemented by one or more processors 202a and 202 b. For example, one or more processors 202 a and 202 b mayimplement one or more layers (e.g., functional layers such as PHY(physical), MAC (media access control), RLC (radio link control), PDCP(packet data convergence protocol), RRC (radio resource control), SDAP(service data adaptation protocol)). One or more processors 202 a and202 b may generate one or more protocol data units (PDUs), one or moreservice data unit (SDU), messages, control information, data orinformation according to the descriptions, functions, procedures,proposals, methods and/or operational flowcharts disclosed herein. Oneor more processors 202 a and 202 b may generate PDUs, SDUs, messages,control information, data or information according to the functions,procedures, proposals and/or methods disclosed herein and provide thePDUs, SDUs, messages, control information, data or information to one ormore transceivers 206 a and 206 b. One or more processors 202 a and 202b may receive signals (e.g., baseband signals) from one or moretransceivers 206 a and 206 b and acquire PDUs, SDUs, messages, controlinformation, data or information according to the descriptions,functions, procedures, proposals, methods and/or operational flowchartsdisclosed herein.

One or more processors 202 a and 202 b may be referred to ascontrollers, microcontrollers, microprocessors or microcomputers. One ormore processors 202 a and 202 b may be implemented by hardware,firmware, software or a combination thereof. For example, one or moreapplication specific integrated circuits (ASICs), one or more digitalsignal processors (DSPs), one or more digital signal processing devices(DSPDs), programmable logic devices (PLDs) or one or more fieldprogrammable gate arrays (FPGAs) may be included in one or moreprocessors 202 a and 202 b. The descriptions, functions, procedures,proposals, methods and/or operational flowcharts disclosed herein may beimplemented using firmware or software, and firmware or software may beimplemented to include modules, procedures, functions, etc. Firmware orsoftware configured to perform the descriptions, functions, procedures,proposals, methods and/or operational flowcharts disclosed herein may beincluded in one or more processors 202 a and 202 b or stored in one ormore memories 204 a and 204 b to be driven by one or more processors 202a and 202 b. The descriptions, functions, procedures, proposals, methodsand/or operational flowcharts disclosed herein implemented usingfirmware or software in the form of code, a command and/or a set ofcommands.

One or more memories 204 a and 204 b may be coupled with one or moreprocessors 202 a and 202 b to store various types of data, signals,messages, information, programs, code, instructions and/or commands. Oneor more memories 204 a and 204 b may be composed of read only memories(ROMs), random access memories (RAMs), erasable programmable read onlymemories (EPROMs), flash memories, hard drives, registers, cachememories, computer-readable storage mediums and/or combinations thereof.One or more memories 204 a and 204 b may be located inside and/oroutside one or more processors 202 a and 202 b. In addition, one or morememories 204 a and 204 b may be coupled with one or more processors 202a and 202 b through various technologies such as wired or wirelessconnection.

One or more transceivers 206 a and 206 b may transmit user data, controlinformation, radio signals/channels, etc. described in the methodsand/or operational flowcharts of the present disclosure to one or moreother apparatuses. One or more transceivers 206 a and 206 b may receiveuser data, control information, radio signals/channels, etc. describedin the methods and/or operational flowcharts of the present disclosurefrom one or more other apparatuses. In addition, one or moretransceivers 206 a and 206 b may be coupled with one or more antennas208 a and 208 b, and may be configured to transmit/receive user data,control information, radio signals/channels, etc. described in thedescriptions, functions, procedures, proposals, methods and/oroperational flowcharts disclosed herein through one or more antennas 208a and 208 b. In the present disclosure, one or more antennas may be aplurality of physical antennas or a plurality of logical antennas (e.g.,antenna ports). One or more transceivers 206 a and 206 b may convert thereceived radio signals/channels, etc. from RF band signals to basebandsignals, in order to process the received user data, controlinformation, radio signals/channels, etc. using one or more processors202 a and 202 b. One or more transceivers 206 a and 206 b may convertthe user data, control information, radio signals/channels processedusing one or more processors 202 a and 202 b from baseband signals intoRF band signals. To this end, one or more transceivers 206 a and 206 bmay include (analog) oscillator and/or filters.

FIG. 25 illustrates a signal process circuit for a transmission signal,in accordance with an embodiment of the present disclosure. Theembodiment of FIG. 25 may be combined with various embodiments of thepresent disclosure.

Referring to FIG. 25 , a signal processing circuit 300 may includescramblers 310, modulators 320, a layer mapper 330, a precoder 340,resource mappers 350, and signal generators 360. For example, anoperation/function of FIG. 25 may be performed by the processors 202 aand 202 b and/or the transceivers 36 and 206 of FIG. 24 . Hardwareelements of FIG. 25 may be implemented by the processors 202 a and 202 band/or the transceivers 36 and 206 of FIG. 24 . For example, blocks 310to 360 may be implemented by the processors 202 a and 202 b of FIG. 24 .Alternatively, the blocks 310 to 350 may be implemented by theprocessors 202 a and 202 b of FIG. 24 and the block 360 may beimplemented by the transceivers 36 and 206 of FIG. 24 , and it is notlimited to the above-described embodiment. Codewords may be convertedinto radio signals via the signal processing circuit 300 of FIG. 25 .Herein, the codewords are encoded bit sequences of information blocks.The information blocks may include transport blocks (e.g., a UL-SCHtransport block, a DL-SCH transport block). The radio signals may betransmitted through various physical channels (e.g., a PUSCH and aPDSCH).

Specifically, the codewords may be converted into scrambled bitsequences by the scramblers 310. Scramble sequences used for scramblingmay be generated based on an initialization value, and theinitialization value may include ID information of a wireless device.The scrambled bit sequences may be modulated to modulation symbolsequences by the modulators 320. A modulation scheme may includepi/2-Binary Phase Shift Keying (pi/2-BPSK), m-Phase Shift Keying(m-PSK), and m-Quadrature Amplitude Modulation (m-QAM).

Complex modulation symbol sequences may be mapped to one or moretransport layers by the layer mapper 330. Modulation symbols of eachtransport layer may be mapped (precoded) to corresponding antennaport(s) by the precoder 340. Outputs z of the precoder 340 may beobtained by multiplying outputs y of the layer mapper 330 by an N*Mprecoding matrix W. Herein, N is the number of antenna ports and M isthe number of transport layers. The precoder 340 may perform precodingafter performing transform precoding (e.g., DFT) for complex modulationsymbols. Alternatively, the precoder 340 may perform precoding withoutperforming transform precoding.

The resource mappers 350 may map modulation symbols of each antenna portto time-frequency resources. The time-frequency resources may include aplurality of symbols (e.g., a CP-OFDMA symbols and DFT-s-OFDMA symbols)in the time domain and a plurality of subcarriers in the frequencydomain. The signal generators 360 may generate radio signals from themapped modulation symbols and the generated radio signals may betransmitted to other devices through each antenna. For this purpose, thesignal generators 360 may include Inverse Fast Fourier Transform (IFFT)modules, Cyclic Prefix (CP) inserters, Digital-to-Analog Converters(DACs), and frequency up-converters.

Signal processing procedures for a signal received in the wirelessdevice may be configured in a reverse manner of the signal processingprocedures of FIG. 25 . For example, the wireless devices (e.g., 200 aand 200 b of FIG. 24 ) may receive radio signals from the exteriorthrough the antenna ports/transceivers. The received radio signals maybe converted into baseband signals through signal restorers. To thisend, the signal restorers may include frequency downlink converters,Analog-to-Digital Converters (ADCs), CP remover, and Fast FourierTransform (FFT) modules. Next, the baseband signals may be restored tocodewords through a resource demapping procedure, a postcodingprocedure, a demodulation processor, and a descrambling procedure. Thecodewords may be restored to original information blocks throughdecoding. Therefore, a signal processing circuit (not illustrated) for areception signal may include signal restorers, resource demappers, apostcoder, demodulators, descramblers, and decoders.

FIG. 26 illustrates a wireless device, in accordance with an embodimentof the present disclosure. The embodiment of FIG. 26 may be combinedwith various embodiments of the present disclosure.

Referring to FIG. 26 , a wireless device 300 may correspond to thewireless devices 200 a and 200 b of FIG. 24 and include variouselements, components, units/portions and/or modules. For example, thewireless device 300 may include a communication unit 310, a control unit(controller) 320, a memory unit (memory) 330 and additional components340.

The communication unit 410 may include a communication circuit 412 and atransceiver(s) 414. The communication unit 410 may transmit and receivesignals (e.g., data, control signals, etc.) to and from other wirelessdevices or base stations. For example, the communication circuit 412 mayinclude one or more processors 202 a and 202 b and/or one or morememories 204 a and 204 b of FIG. 24 . For example, the transceiver(s)414 may include one or more transceivers 206 a and 206 b and/or one ormore antennas 208 a and 208 b of FIG. 42 .

The control unit 420 may be composed of at least one processor set. Forexample, the control unit 420 may be composed of a set of acommunication control processor, an application processor, an electroniccontrol unit (ECU), a graphic processing processor, a memory controlprocessor, etc. The control unit 420 may be electrically coupled withthe communication unit 410, the memory unit 430 and the additionalcomponents 440 to control overall operation of the wireless device. Forexample, the control unit 420 may control electrical/mechanicaloperation of the wireless device based on aprogram/code/instruction/information stored in the memory unit 430. Inaddition, the control unit 420 may transmit the information stored inthe memory unit 430 to the outside (e.g., another communication device)through the wireless/wired interface using the communication unit 410over a wireless/wired interface or store information received from theoutside (e.g., another communication device) through the wireless/wiredinterface using the communication unit 410 in the memory unit 430.

The memory unit 430 may be composed of a random access memory (RAM), adynamic RAM (DRAM), a read only memory (ROM), a flash memory, a volatilememory, a non-volatile memory and/or a combination thereof. The memoryunit 430 may store data/parameters/programs/codes/commands necessary toderive the wireless device 400. In addition, the memory unit 430 maystore input/output data/information, etc.

The additional components 440 may be variously configured according tothe types of the wireless devices. For example, the additionalcomponents 440 may include at least one of a power unit/battery, aninput/output unit, a driving unit or a computing unit. Without beinglimited thereto, the wireless device 400 may be implemented in the formof the robot (FIG. 41 , 100 a), the vehicles (FIG. 41 , 100 b-1 and 100b-2), the XR device (FIG. 41 , 100 c), the hand-held device (FIG. 41 ,100 d), the home appliance (FIG. 41 , 100 e), the IoT device (FIG. 41 ,100 f), a digital broadcast terminal, a hologram apparatus, a publicsafety apparatus, an MTC apparatus, a medical apparatus, a Fintechdevice (financial device), a security device, a climate/environmentdevice, an AI server/device (FIG. 41 , 140), the base station (FIG. 41 ,120), a network node, etc. The wireless device may be movable or may beused at a fixed place according to use example/service.

FIG. 27 illustrates a hand-held device, in accordance with an embodimentof the present disclosure. FIG. 27 exemplifies a hand-held deviceapplicable to the present disclosure. The hand-held device may include asmartphone, a smart pad, a wearable device (e.g., a smart watch or smartglasses), and a hand-held computer (e.g., a laptop, etc.). Theembodiment of FIG. 27 may be combined with various embodiments of thepresent disclosure.

Referring to FIG. 27 , the hand-held device 500 may include an antennaunit (antenna) 508, a communication unit (transceiver) 510, a controlunit (controller) 520, a memory unit (memory) 530, a power supply unit(power supply) 540 a, an interface unit (interface) 540 b, and aninput/output unit 540 c. An antenna unit (antenna) 508 may be part ofthe communication unit 510. The blocks 510 to 530/440 a to 540 c maycorrespond to the blocks 310 to 330/340 of FIG. 26 , respectively, andduplicate descriptions are omitted.

The communication unit 510 may transmit and receive signals and thecontrol unit 520 may control the hand-held device 500, and the memoryunit 530 may store data and so on. The power supply unit 540 a maysupply power to the hand-held device 500 and include a wired/wirelesscharging circuit, a battery, etc. The interface unit 540 b may supportconnection between the hand-held device 500 and another external device.The interface unit 540 b may include various ports (e.g., an audioinput/output port and a video input/output port) for connection with theexternal device. The input/output unit 540 c may receive or output videoinformation/signals, audio information/signals, data and/or user inputinformation. The input/output unit 540 c may include a camera, amicrophone, a user input unit, a display 540 d, a speaker and/or ahaptic module.

For example, in case of data communication, the input/output unit 540 cmay acquire user input information/signal (e.g., touch, text, voice,image or video) from the user and store the user inputinformation/signal in the memory unit 530. The communication unit 510may convert the information/signal stored in the memory into a radiosignal and transmit the converted radio signal to another wirelessdevice directly or transmit the converted radio signal to a basestation. In addition, the communication unit 510 may receive a radiosignal from another wireless device or the base station and then restorethe received radio signal into original information/signal. The restoredinformation/signal may be stored in the memory unit 530 and then outputthrough the input/output unit 540 c in various forms (e.g., text, voice,image, video and haptic).

FIG. 28 illustrates a car or an autonomous vehicle, in accordance withan embodiment of the present disclosure. FIG. 28 exemplifies a car or anautonomous driving vehicle applicable to the present disclosure. The caror the autonomous driving car may be implemented as a mobile robot, avehicle, a train, a manned/unmanned aerial vehicle (AV), a ship, etc.and the type of the car is not limited. The embodiment of FIG. 28 may becombined with various embodiments of the present disclosure

Referring to FIG. 28 , the car or autonomous driving car 600 may includean antenna unit (antenna) 608, a communication unit (transceiver) 610, acontrol unit (controller) 620, a driving unit 640 a, a power supply unit(power supply) 640 b, a sensor unit 640 c, and an autonomous drivingunit 640 d. The antenna unit 650 may be configured as part of thecommunication unit 610. The blocks 610/630/640 a to 640 d correspond tothe blocks 510/530/540 of FIG. 27 , and duplicate descriptions areomitted.

The communication unit 610 may transmit and receive signals (e.g., data,control signals, etc.) to and from external devices such as anothervehicle, a base station (e.g., a base station, a road side unit, etc.),and a server. The control unit 620 may control the elements of the caror autonomous driving car 600 to perform various operations. The controlunit 620 may include an electronic control unit (ECU). The driving unit640 a may drive the car or autonomous driving car 600 on the ground. Thedriving unit 640 a may include an engine, a motor, a power train,wheels, a brake, a steering device, etc. The power supply unit 640 b maysupply power to the car or autonomous driving car 600, and include awired/wireless charging circuit, a battery, etc. The sensor unit 640 cmay obtain a vehicle state, surrounding environment information, userinformation, etc. The sensor unit 640 c may include an inertialnavigation unit (IMU) sensor, a collision sensor, a wheel sensor, aspeed sensor, an inclination sensor, a weight sensor, a heading sensor,a position module, a vehicle forward/reverse sensor, a battery sensor, afuel sensor, a tire sensor, a steering sensor, a temperature sensor, ahumidity sensor, an ultrasonic sensor, an illumination sensor, a brakepedal position sensor, and so on. The autonomous driving sensor 640 dmay implement technology for maintaining a driving lane, technology forautomatically controlling a speed such as adaptive cruise control,technology for automatically driving the car along a predeterminedroute, technology for automatically setting a route when a destinationis set and driving the car, etc.

For example, the communication unit 610 may receive map data, trafficinformation data, etc. from an external server. The autonomous drivingunit 640 d may generate an autonomous driving route and a driving planbased on the acquired data. The control unit 620 may control the drivingunit 640 a (e.g., speed/direction control) such that the car orautonomous driving car 600 moves along the autonomous driving routeaccording to the driving plane. During autonomous driving, thecommunication unit 610 may aperiodically/periodically acquire latesttraffic information data from an external server and acquire surroundingtraffic information data from neighboring cars. In addition, duringautonomous driving, the sensor unit 640 c may acquire a vehicle stateand surrounding environment information. The autonomous driving unit 640d may update the autonomous driving route and the driving plan based onnewly acquired data/information. The communication unit 610 may transmitinformation such as a vehicle location, an autonomous driving route, adriving plan, etc. to the external server. The external server maypredict traffic information data using AI technology or the like basedon the information collected from the cars or autonomous driving carsand provide the predicted traffic information data to the cars orautonomous driving cars.

Examples of the above-described proposed methods may be included as oneof the implementation methods of the present disclosure and thus may beregarded as kinds of proposed methods. In addition, the above-describedproposed methods may be independently implemented or some of theproposed methods may be combined (or merged). The rule may be definedsuch that the base station informs the UE of information on whether toapply the proposed methods (or information on the rules of the proposedmethods) through a predefined signal (e.g., a physical layer signal or ahigher layer signal).

Those skilled in the art will appreciate that the present disclosure maybe carried out in other specific ways than those set forth hereinwithout departing from the spirit and essential characteristics of thepresent disclosure. The above exemplary embodiments are therefore to beconstrued in all aspects as illustrative and not restrictive. The scopeof the disclosure should be determined by the appended claims and theirlegal equivalents, not by the above description, and all changes comingwithin the meaning and equivalency range of the appended claims areintended to be embraced therein. Moreover, it will be apparent that someclaims referring to specific claims may be combined with another claimsreferring to the other claims other than the specific claims toconstitute the embodiment or add new claims by means of amendment afterthe application is filed.

Industrial Availability

The embodiments of the present disclosure are applicable to variousradio access systems. Examples of the various radio access systemsinclude a 3^(rd) generation partnership project (3GPP) or 3GPP2 system.

The embodiments of the present disclosure are applicable not only to thevarious radio access systems but also to all technical fields, to whichthe various radio access systems are applied. Further, the proposedmethods are applicable to mmWave and THzWave communication systems usingultrahigh frequency bands.

Additionally, the embodiments of the present disclosure are applicableto various applications such as autonomous vehicles, drones and thelike.

1-16. (canceled)
 17. A method of operating a first terminal in awireless communication system, the method comprising: transmitting firstmessages requesting to transmit a positioning reference signal (PRS);receiving a second message related to the PRS; transmitting a thirdmessage including scheduling information for transmitting the PRS usingat least one transmit beam, indicated by the second message, among theplurality of transmit beams; receiving PRSs; measuring timing of thereceived PRSs; and performing an operation for positioning based on thetimings, wherein the first message is transmitted by using a pluralityof transmit beams, and wherein at least one PRS of the PRSs istransmitted at a second terminal based on the scheduling information inthe third message.
 18. The method of claim 17, wherein the firstmessages include information indicating that transmission of the PRS isrequested or is transmitted through a resource pool corresponding totransmission of the PRS.
 19. The method of claim 17, wherein the firstmessages include information related to a resource for transmitting thesecond message.
 20. The method of claim 19, wherein the informationrelated to the resource is differently set according to a transmit beamused to transmit the first messages.
 21. The method of claim 17, whereinthe second message includes information indicating the at least onetransmit beam or is transmitted through a resource pool corresponding tothe at least one transmit beam.
 22. The method of claim 17, wherein thesecond message includes information related to a resource fortransmitting the third message.
 23. The method of claim 17, wherein thethird message is repeatedly transmitted using a transmit beam indicatedby the second message.
 24. The method of claim 17, wherein the PRS isreceived using a receive beam corresponding to a transmit beam indicatedby the second message.
 25. The method of claim 17, further comprising:receiving location information of the second terminal or locationinformation of a fixed reference that the second terminal has.
 26. Afirst terminal in a wireless communication system, the first terminalcomprising: a transceiver; and a processor coupled to the transceiverand configured to: transmit first messages requesting to transmit apositioning reference signal (PRS); receive a second message related tothe PRS; transmit a third message including scheduling information fortransmitting the PRS using at least one transmit beam, indicated by thesecond message, among the plurality of transmit beams; and receive PRSs;measuring timing of the received PRSs; and performing an operation forpositioning based on the timings, wherein the first message istransmitted by using a plurality of transmit beams, and wherein at leastone PRS of the PRSs is transmitted at a second terminal based on thescheduling information in the third message.
 27. The first terminal ofclaim 26, wherein the first messages include information indicating thattransmission of the PRS is requested or is transmitted through aresource pool corresponding to transmission of the PRS.
 28. The firstterminal of claim 26, wherein the first messages include informationrelated to a resource for transmitting the second message.
 29. The firstterminal of claim 28, wherein the information related to the resource isdifferently set according to a transmit beam used to transmit the firstmessages.
 30. The first terminal of claim 26, wherein the second messageincludes information indicating the at least one transmit beam or istransmitted through a resource pool corresponding to the at least onetransmit beam.
 31. The first terminal of claim 26, wherein the secondmessage includes information related to a resource for transmitting thethird message.
 32. The first terminal of claim 26, wherein the thirdmessage is repeatedly transmitted using a transmit beam indicated by thesecond message.
 33. The first terminal of claim 26, wherein the PRS isreceived using a receive beam corresponding to a transmit beam indicatedby the second message.
 34. The first terminal of claim 26, furthercomprising: receiving location information of the second terminal orlocation information of a fixed reference that the second terminal has.35. A device comprising at least one memory and at least one processorfunctionally connected to the at least one memory, wherein the at leastone processor controls the device to: transmit first messages requestingto transmit a positioning reference signal (PRS); receive a secondmessage related to the PRS; transmit a third message includingscheduling information for transmitting the PRS using at least onetransmit beam, indicated by the second message, among the plurality oftransmit beams; and receive PRSs; measuring timing of the received PRSs;and performing an operation for positioning based on the timings,wherein the first message is transmitted by using a plurality oftransmit beams, and wherein at least one PRS of the PRSs is transmittedat a terminal based on the scheduling information in the third message.